Dropbox Bug Can Permanently Lose Your Files

published by Eric Mill on

127 of my files in Dropbox are now gone forever, due to a bug where files were "updated" to be 0 bytes, and Dropbox lost its previous copy of the file.

2 other files (precious family photos) were also affected, but it happened recently enough to be recovered manually by Dropbox engineers. 23 other files were also turned to 0 byte dust, but Dropbox kept its version history of these and I could revert them to their original version.

Check whether you've been affected (on Mac or Linux) by running this command in a Terminal, it'll spit out a list of 0-byte files to a text file on your desktop.

find /path/to/your/Dropbox -size 0 -type f > ~/Desktop/zero-byte-files.txt

Important: Make sure you sanity check the list. Some systems have hidden 0-byte files, such as Macs' "Icon\r", that are expected and normal.

If you find any that look unexpected, let Dropbox know, and reference this blog post to them so they can connect it with the issue I reported.

I've included my correspondence with Dropbox on the issue below. They've been very nice about it, and are looking into it, but this is a very serious bug. Because they don't know what the bug is, potentially anyone could be affected. I'll update this post if they find a fix.

Update: Some folks on Hacker News, and Matt Holden of Dropbox in the comments, have raised the possibility of filesystem corruption, particularly because of a recently reported ext4 bug. I do use ext4, so this can plausibly explain why my files were 0-byte'd in the first place, and why others have reported finding 0-byte'd files.

I also do not use Packrat, a premium Dropbox feature that stores version history for longer than 30 days, so this could plausibly explain why my 127 files that had been 0-byte'd months ago no longer have a version history of before then. I wasn't aware of the 30-day window.

However, these do not plausibly explain why the 2 manually recovered files that had recently been 0-byte'd, well within the 30-day window, showed no pre-0-byte version history, and required the assistance of Dropbox engineers.

It could be that the bug here has nothing to do with their desktop client - it could be a version history bug in the web frontend that affects some recently edited files. If that's the case, then that still needs to be fixed, so that people in my position can recover files their disk corrupted before they pass out of the 30-day window. It's only by finding and fixing that website bug that Dropbox can say with confidence that there's no desktop client bug.

Update 2: A report by someone who is on OS X, uses Packrat, but has lost 70 files they can't recover.

Original correspondence

Eric Mill, Oct 20 05:50 pm (PDT):

Hi,

I recently wiped my hard drive and reinstalled my OS (clean upgrade from Ubuntu 12.04 to 12.10). I had been running Dropbox on the old OS. When I installed Dropbox on the new OS, almost everything went very smoothly. However, for some unknown reason, 25 files were "edited" to become 0-byte files.

This took place over 3 "events", at 3:49 PM, 5:31 PM, and 5:45 PM that afternoon:
https://www.dropbox.com/events/[redacted]
https://www.dropbox.com/events/[redacted]
https://www.dropbox.com/events/[redacted]

As far as I know, nothing I did caused these to happen. I didn't interact with these files, and in fact, I took care not to make any destructive actions in my Dropbox folder during the long syncing process. I believe these are bugs in Dropbox's syncing logic, but I have no idea how to reproduce it, or what common thread ties these files and events together.

I am able to restore each file from Dropbox's version history, though the user experience for this process is pretty annoying - I have to navigate through the file system for each one. There's no way to jump from an "event" screen that lists the affected files to a file's version history screen.

In general, I'm pretty happy with Dropbox, but this was a pretty alarming bug. I hope there's something you can do to look into why it happened.

Thanks,
Eric


Ridwan - Dropbox Support, Oct 22 05:11 pm (PDT):

Hi Eric,

Terribly sorry about the delayed response on this support request. In reviewing your account you appear to have restored most of these files via the web interface (I restored one extra).

Is there anything further I can assist you with?

I'm not aware of any bugs in the client syncing process at this moment, but I'll pass your case along to our engineering team. Hope this helps! Please let me know if I can be of any other assistance.

Best,
Ridwan


Eric Mill, Oct 23 07:37 am (PDT):

Yeah, there is one other piece of assistance I need - in restoring the files one by one, I noticed there were two that seem to have lost their history entirely:

https://www.dropbox.com/revisions/[redacted]
https://www.dropbox.com/revisions/[redacted]

These two files were the first two marked as "Edited" in the third Dropbox event along with a bunch of other files, the rest of whom have an earlier version I could restore. These two do not, yet they definitely had an earlier version that was not 0 bytes. Dropbox describes the event as "Edited", which clearly implies there was an earlier version.

Again, I have no idea why these 25 files, among my entire Dropbox, were affected, or why these 2 were affected differently from the other 23. These 2 files are now lost to me.

I would ask that you take this as a serious bug report. Even if your engineering team were to write off my original report of 25 files being 0-byte'd as my own human error (which it wasn't), the state of these two files indicate an undeniable bug in Dropbox's software (which in turn strongly suggests that all 25 were affected by a Dropbox bug).

If you can restore my files somehow, that would be greatly appreciated. Thankfully, these are just a couple of random photos - but I have other, more irreplaceable files contained in Dropbox, and if I were to lose them I would be very upset.

-- Eric


David M. - Dropbox Support, Oct 23 05:30 pm (PDT):

Hi Eric,

I've reported this to our engineers and they are taking a further look into the issue. To help troubleshoot the issue can you run the following in Terminal:

find /home/eric/.dropbox_actual/Dropbox -size 0 > ~/Desktop/zerodump

This should generate a text file on your Desktop. Can you attach that file to your reply so we can see if there are any additional files that are 0 bytes in your Dropbox folder. Please also note there may be some false positives as some applications will create 0 byte log/temp files.

Additionally, can you let us know of any system events that may have occurred during the time frames for those changesets?

Thanks!

Best,
David


Eric Mill, Oct 24 07:07 am (PDT):

Hi David,

Thank you for the prompt response. That's a good suggestion, I ran the command and have attached the file. I should have thought of that myself.

There are more files than I expected listed as 0 bytes. The one that's marked as deleted and is in the dropbox cache folder is one that I deleted myself on the same day as the events in question, before I realized what was going on. Many of the rest are apparently from earlier in the year - for example, one is this, from May 20th:
https://www.dropbox.com/revisions/[redacted]

May 20th is somewhat near when I last upgraded Ubuntu, but I'm pretty sure I did that much earlier in May, soon after Ubuntu's release. This one also lacks a previous version to restore, which is alarming.

I don't know what specific system events would have transpired during the events in question, either in May or October. In October, the 3 events I originally referenced occurred throughout the late afternoon, during the hours after installation of Dropbox in which it was syncing ~11GB of data down to my laptop. During this time, I was re/installing other drivers and software, occasionally rebooting, and configuring things like my /etc/fstab and my /etc/X11/xorg.conf files.

The only thing I can think of that might have been related is that, somewhere in the middle of that, I added the user_xattr flag to the partition on which my Dropbox lives, and rebooted (which caused a remount). My understanding is that the user_xattr flag is a pretty harmless option, that allows applications that care about such things to add arbitrary filesystem attributes.

Unfortunately, I don't have system logs from that time - because I have an SSD, I mount my logs directory into RAM (to minimize disk writes) and it gets wiped on every reboot. Still, if you have any other questions I'm happy to try to answer them.

-- Eric


David M. - Dropbox Support, Oct 25 02:48 pm (PDT):

Hi Eric,

I was able to have our web team recover the two files:

https://www.dropbox.com/revisions/[redacted]
https://www.dropbox.com/revisions/[redacted]

Unfortunately, it looks like the files that were previously 0 byted can no longer be recovered as their previous versions were removed from our servers as the events occurred in June. I sincerely apologize for this file loss.

Thank you for the additional information you were able to provide about the events, I'll be continuing to follow up with our engineering team to try and find the root cause of this issue. I'll let you know as soon as we have any news.

If you have any additional questions or concerns please let me know.

Best,
David

  1. lliseil

    What happened to Ash just happened to me:

    A bunch of up-to-date files and folders (total ~8GB) on the main computer. Dropbox's sync up to date. Launched Dropbox on computer 2 that had an older version of these documents. Then re-launched Dropbox on computer 1 (same LAN) and went to bed, and waited till Dropbox on both computers say "up to date" before closing them.

    I soon noticed some folders and documents where missing on computer 2. « That's strange! Well OK, since the're still on my main machine I'll sync them another way. » Then I realized the data had been deleted on computer 1 as well, GASP!

    Run to dropbox.com, login, and go to "Events": and amongst many events, read « You deleted 4973 files. » WTH? While on Dropbox.com I opened a folder then another etc (tells it to display the deleted files): each one had a random number of deleted folders and files.

    I'm so glad I had a backup from that day! While technically possible, restoring from dropbox.com by myself would have been unrealistic with hundreds of folder to open and restore one after the other.

    For the record, rsync from the backup says it all:

    Number of files: 36,552 (reg: 34,701, dir: 1,573, link: 278)
    Number of created files: 5,496 (reg: 5,040, dir: 427, link: 29) Number of deleted files: 0 Meaning that 5.496 files were deleted on computer 1 in the Dropbox process. Whether it's a bug in Dropbox's "LAN" feature, or that I shouldn't have do the way I did, I'll never even think of Dropbox as a backup app.

  2. Ash

    My computer is not backed up thru Time Machine :/ I know... dumb of me.

  3. Ash

    Everything on my desktop disappeared one at a time while installing dropbox to my MAC. I have no idea where the files went... very important files... that I really need to get back. Any advice? Apple was unable to help.... they told me I should speak with a third party, but this is ridiculous. Everything gets wiped off my desktop except for a "Contents" folder with a bunch of DropBox files all in it... I don't understand. DropBox won't reply to my request for help they keep telling me to contact Apple, but it is them I need to speak with!!!!

    Any Advice? Please

  4. Barbara

    I have the same problem. I installed Yosemite 10.10.1. Everything was fine. When I downloaded dropbox I lost everything I had in my desktop

  5. stu

    I recently discovered that about 200 files between 10/29/10 and 10/3/13 were corrupted and unrecoverable...beyond the 30 days and I never knew about packrat before this discovery. I'm working on restoring some of these files from a local drive. This certainly lowers my confidence in Dropbox and is going to make me look at Box and other cloud based sites.

  6. Jay Dorsey

    For Mac users who find this post, don't rule out the bug with Clusters like J (previous comment) mentioned. When I opened Clusters just a moment ago it prompted me for an update with the message below:

    "If you used an old version of Clusters in any of the Mavericks developer betas and run into this issue, please upgrade and contact support@latenitesoft.com so we can help you fix the affected files."

    My 0kb files were completely outside of my Dropbox folder so Dropbox probably never touched them (in my case).

    Thanks for the post—I never would have thought to check had I not seen the recent comment noting Clusters as a possible cause.

  7. J

    Clusters did it for me. When I upgraded to Mavericks I re-installed it even though I was told it was incompatible. It reset the files to 0.

  8. Eric

    @Ruthanne: Use Dropbox's support form here:

    https://www.dropbox.com/support

  9. Ruthanne

    I accidentally deleted a video that was saved in my Dropbox . I looked up how to retrieve deleted files and they told me to download the paid version of Dropbox then download pack rat . It does not work after I did all this and click on the deleted video nothing happens. There is also no way to contact Dropbox support team, if they have one, for help. CAN ANYONE HELP ME?????????

  10. pure garcinia cambogia dosage

    If you are what is commonly described as a "bored eater," there is a good chance that you will still continue to eat. The main key nutrient of the popular dietary supplement Primal Lean is irvingia gabonensis (bush mango). They will want to eat less and thus decrease the amount they consume.

  11. alex

    Keep up the good work.

  12. Jane

    Here is an email thread that is still ongoing regarding files that suddenly showed up as 0 KB files on one of my Dropbox folders that was a shared folder. As you can see "David" and "Hanz" believe in the 'history' that Dropbox attaches to each file. But something weird happened and it was not even completely recoverable in Pack Rat. Especially the ones that are being accused of being uploaded incorrectly. Start from the bottom of this post to see the first email.

    The final email sent by me: (still waiting to hear from them)

    So, no one answered my last email so I will repeat the contents here:

    "By the way, the internet has quite a few reports of the problems with Dropbox and the 0 byte files. I really don't want to talk to Hanz anymore, since he is like talking to a recording.

    "I uploaded files from a Mac computer that showed MORE than 0 bytes. Dropbox showed that I had used up 50% of my 100GB+ allotment. How is anyone supposed to know if that indicator is real? I assume that when I see that my Dropbox allotment is being used up, that there are real files with real sizes in there. Especially when I see that the size of my Dropbox contents remains that high for several weeks.

    "Suddenly, i have only 15% of 112 GB used (and some of this is duplicates because it is so tiresome to keep trying to go back and figure out if a picture was deleted and needs to be restored. This has nothing to do with what Hanz said....which he repeats in an infuriatingly monotone manner. IF the the file uploaded and the whole history that YOU SEE only shows 0 bytes, then how did I SEE it showing 50 GB USED once upon a time? I even bought more space because I WAS RUNNING OUT OF SPACE. You should refund me, since I don't need the space now that you have somehow corrupted my files. And why did it do this mostly to all of my videos?

    "So once and for all: IF MY DROPBOX SHOWS THAT I HAVE USED 50%, IS THAT TRUE? OR DO I HAVE TO WAIT FOR SOME PERIOD OF TIME TO CONFIRM THIS? Why would it go DOWN if I didn't delete anything and even if I did, why wouldn't the deleted files be in my Pack rat?

    "I have been looking at the history of some of the pictures. Some of them show that it was uploaded as a zero byte file, then suddenly it is a real file and the goes back to being a zero byte file and then gets restored. All back and forth. how does this happen? For example, please see IMG_8068.JPG.

    "The other odd thing is that this mostly happened to my pictures taken in April. On the same album, trip, upload, the March pictures are okay. Even the March videos are okay. All of the photos were uploaded to Dropbox after I got home on April 7. When I had all my photos and videos for that Europe Trip, there were over a thousand. Now I have less than 200.

    "This also was the only folder I have that was a shared folder. At one point, I saw that "Neville" had done some altering on many pictures. I don't know anyone by that name and I don't remember where I saw his name.

    "Please have someone other than Hanz carefully read what I said. Jane"

    This was sent more than a day ago and I haven't heard back.

    In the mean time, I had an idea. I decided to call one of my friends who was part of the shared folder and ask her if she was able to download my photos from the mysteriously disappearing/0 Kb file folder.

    I was delighted to hear that she had downloaded the whole original file...the one that had ONE THOUSAND THREE HUNDRED AND NINETEEN PHOTOS AND VIDEOS IN IT. The one that now only has 100-200 photos and barely any of the videos. The one that you said I mistakenly uploaded 0 byte files to.

    Please check and observe the files in the folder "Europe '13 River Cruise- Mead?"

    In it are all of the files that I originally uploaded. And since my friend could download them to her computer, I guess they must have not been 'uploaded as 0 byte files' as your "History" claims that they were.

    So, again, what is the bug here? Something corrupted the history that you so revere like it's the Bible. The famous history that you consistently referred to as gospel is wrong. MY VIDEOS AND PHOTOS WERE UPLOADED WELL ENOUGH TO ALLOW SOMEONE ELSE TO SHARE AND DOWNLOAD THEM AND THEN BE ABLE TO SHARE THEM BACK.

    Why?

    Don't you care enough to get to the bottom of this? This is scary. i am saving this email thread because people need to know what they are getting when they buy Dropbox and they need to know how to manage it so that the handling of shared files is done in a manner that preserves the goal of putting the file in dropbox in the first place: Safe sharing and storage.

    Sent from my iPad

    On Jul 8, 2013, at 3:37 PM, Hanz notifications-support@dropbox.zendesk.com wrote:

    IMPORTANT ## Text below this line won't be added to the ticket

    You can add a response by replying to this email.

    Please be sure to reply with the same email address that you used to originally contact us.

    Hanz, Jul 08 03:36 pm (PDT): Hi Jane,

    The answer to that question doesn't fall within the scope of Dropbox since there are no registries that show that those files were once bigger than 0bytes.

    Your account under "uclapt@yahoo.com" is currently reporting: Quota: 16% - 17.5 GB / 112.88 GB 0 bytes in shares.

    Connectivity issues may delay the actual space of your Dropbox, but please note that the size in your hard drive doesn't necessarily mean that the size of your Dropbox has been immediately updated.

    You can use any OS you want as long as you make sure that the complete files were uploaded to Dropbox.

    Best, Hanz

    Jane Mead, Jul 08 12:05 pm (PDT): I have read this info multiple times now. What you have not answered is why would my dropbox fill up with 50GB if it is full of 0kb files and then suddenly drop down to 15 gb?

    How can you tell if the files are complete? I always waited hours for the video files to upload and made sure that the icon was not the one that shows that the file is still in progress. Do I just not use a Mac?

    (Sent from my iPhone, please excuse typos.)

    Hanz, Jul 08 11:27 am (PDT): Hi Jane,

    All activity is controlled by the clients and never by the servers. The Dropbox software only responds to changes after they happen. The Dropbox servers do not have the ability to modify your files on their own.

    As my teammate David already stated, it appears that the files in that folder did not upload correctly into the Dropbox folder when first added. You'll notice that the files are only 0 bytes in size, effectively empty. This type of issue occurs when transferring images from a camera or external hard drive to your computer.

    This can also happen specifically on an Apple Mac computer or a Linux computer when a large file or a large number of files are being moved on that computer. Mac's create placeholder 0 byte files in their place until the transfer is complete. If the transfer fails or is stopped before it has fully finished, those 0 byte files will be left in their place. In this case Dropbox syncs whatever files are placed in the Dropbox folder, the empty placeholders.

    Please let me know if there is anything else I can do for you.

    Best, Hanz

    Jane Mead, Jul 05 08:07 pm (PDT): How can they be 'added as zero files, and still show up as taking up chunks of my storage space and then suddenly disappear two weeks later? When is the file really secure then? Why were some of the files in the trash and recoverable and some were not? If I didn't put them in there who did? You have a bug here. I cannot upload this many zero files and not notice! Look how many there are. All in the same album that was the only one that was shared. Do not tell me that I uploaded them wrong. I did what I did with all of the files in my dropbox. What did YOUR program do to my files and how do you stop this from happening again?

    Jane

    (Sent from my iPhone, please excuse typos.)

    Hanz, Jul 05 06:55 pm (PDT): Hi Jane,

    I've restored some of the files you mentioned that used to be in this path: "/2013 European River Cruise Choir Tour/2013 Europe Choir Tour-J. Mead/". Unfortunately, die to the reasons my teammate David stated, the other ones were originally added as 0 byte files. You can trace the history of those files by looking at the "Previous versions" by following these steps:

    1) Log in to the Dropbox website:

    http://www.dropbox.com

    2) Browse to the folder and click on "Show deleted files" (if necessary) 3) Browse to the file you would like to investigate 4) Click the blue arrow to the right of the file 5) Select "Previous versions" from the pull-down menu

    That way you can see that they were indeed added to Dropbox like that.

    Sorry for any inconvenience this causes.

    Best, Hanz

    Jane Mead, Jul 05 04:49 pm (PDT): I see the history, but can you see the history of the volume of my file? Why would it be almost 50% used (out of over 100GB of space) if the files weren't there?

    Please escalate this to someone else. I can see that you are not going to be effective if this is all you are going to say every time.

    Jane

    David M. - Dropbox Support, Jul 05 03:36 pm (PDT): Hi Jane,

    Unfortunately, the files you've pointed out look to have been originally uploaded as a 0 byte file from the device "jane-meads-macbook" during the following event and were never edited other than a deletion and a re-add from a web which may have been a restore:

    https://www.dropbox.com/events/256489758/360968158

    You can see the revision history for a file by looking at the "previous version history" on the web site. For more information, please visit the help center article:

    https://www.dropbox.com/help/11

    Best, David

    Jane Mead, Jul 05 03:24 pm (PDT): David:

    I disagree. The files uploaded completely and had files sizes that took up space on my Dropbox...probably 30GB worth that you could see were listed on my Dropbox total file size. The files were also shareable by others and downloadable. They were originally uploaded ONE FILE AT A TIME from a desktop application on my Mac and I waited good and long before DELETING THEM from my desktop because I trusted Dropbox. It wasn't until three weeks later that I noticed the files were missing (mostly because I suddenly had a ton of space on my Dropbox)

    I was able to restore a lot of the missing ones by going into the deleted folders and restoring. Some of the videos were able to be restored, but the bulk of them are now suddenly 0kb and that is new.

    Something happened on your end...long after my uploading was good and cold.

    Jane

    Sent from my iPad

    David M. - Dropbox Support, Jul 05 02:56 pm (PDT): Hi Jane,

    It appears that the files in that folder did not upload correctly into the Dropbox folder when first added. You'll notice that the files are only 0 bytes in size, effectively empty. This type of issue occurs when transferring images from a camera or external hard drive to your computer. I suggest that you attempt to transfer your files to your computer again from their source.

    It looks like in this case you attempted to upload these files via the web uploader however it didn't completely finish. The Dropbox desktop application can handle files and folders of any size or number and is the preferred method of uploading files. The web site uploader has a limit of 300MB per file and cannot upload folders, only selections of files. For folders or larger files you need to use the Dropbox desktop application.

    This can also happen specifically on an Apple Mac computer or a Linux computer when a large file or a large number of files are being moved on that computer. Mac's create placeholder 0 byte files in their place until the transfer is complete. If the transfer fails or is stopped before it has fully finished, those 0 byte files will be left in their place. In this case Dropbox syncs whatever files are placed in the Dropbox folder, the empty placeholders.

    Best, David

    Jane Mead, Jul 04 12:13 pm (PDT): I sent one email with some files and then also noticed that in the "Photos" file all of those files are also 0 kbytes.

    I know that when I first used Dropbox, my capacity was filled to about halfway and now it is suddenly under 20%. What happened? I did not delete the videos and even if someone did, I have Packrat, so I should be able to restore. At this point, I can't see anything in these files except the name of the file.

    So, to reiterate:

    Here are the files I sent in the last email:

    IMG_8034.MOV IMG_8037.MOV IMG_8040.MOV IMG_8042.MOV IMG_8171.MOV IMG_8199.MOV IMG_8207.MOV IMG_8208.MOV IMG_8463.jpg IMG_8464.MOV IMG_8477.jpg IMG_8479.MOV IMG_8481.MOV IMG_8486.jpg IMG_8487.jpg IMG_8495.jpg

    And here are some others that were not in the Europe Choir Tour file, where they should have been, but were in the Photos File:

    IMG_7819.MOV IMG_7820.MOV IMG_7853.JPG IMG_7875.JPG IMG_7917.JPG IMG_7956.MOV IMG_7957.MOV IMG_7968.MOV IMG_7976.JPG IMG_7990.MOV IMG_7991.MOV IMG_7992.MOV IMG_7993.MOV IMG_7994.MOV IMG_7995.MOV IMG_7996.MOV IMG_7997.JPG IMG_7998.JPG

    Jane


    From: David M. - Dropbox Support notifications-support@dropbox.zendesk.com To: Jane Mead uclapt@yahoo.com Sent: Tuesday, July 2, 2013 2:44 PM Subject: [Dropbox Support] Re: DB: Lost files

    Jane Mead, Jul 04 12:02 pm (PDT): I don't see why you cannot see all of the videos that are now zero bytes...

    Anyway, let me illuminate you

    IMG_8034.MOV IMG_8037.MOV IMG_8040.MOV IMG_8042.MOV IMG_8171.MOV IMG_8199.MOV IMG_8207.MOV IMG_8208.MOV IMG_8463.jpg IMG_8464.MOV IMG_8477.jpg IMG_8479.MOV IMG_8481.MOV IMG_8486.jpg IMG_8487.jpg IMG_8495.jpg

    Jane

    From: David M. - Dropbox Support notifications-support@dropbox.zendesk.com To: Jane Mead uclapt@yahoo.com Sent: Tuesday, July 2, 2013 2:44 PM Subject: [Dropbox Support] Re: DB: Lost files

    David M. - Dropbox Support, Jul 02 02:41 pm (PDT): Hi Jane,

    Thanks for contacting Dropbox.

    Can you tell me the names of the files you're experiencing this issue with so I can investigate this further?

    Best, David

    Jane Mead, Jun 29 04:55 pm (PDT): I purchased Packrat from the beginning. I am not sure what happened, but a significant number of files from one of my folders were deleted. This was a shared folder, although I don't recognize the person who modified the file. I have been able to recover a lot of them, but 2/3 are still showing up as 0KB, especially the videos. What can I do?

    Message-Id:4FC1EHM9_51db3f1adbc43_39cd120f86848456_sprut

  13. Chris

    Bug is still there used dropbox and now its empty, Ive synched it with the iPhone app.

    Could this be the problem.

  14. Justin

    I also lost my entire dropbox, using the linux client. I clean installed from 12.10 to 13.04. My dropbox was pointing to /usr/dropbox/Dropbox (so it would be on my Hard drive not my SSD). On first boot, dropbox of course couldn't find that directory, so I recreated it. It was of course empty. Dropbox instead of syncing my files down, decided I'd deleted 3,700 files from my dropbox. Every single file, the web history reports them as deleted. I've filed a request to get them back a few days ago and have yet to get a response, but be very careful with the linux version of Dropbox. And don't rely on dropbox as your sole backup method.

  15. C Bhushan

    This particular observation is not related. But it looks similar.

    http://flukylogs.blogspot.com/2013/03/dropbox-bug.html

  16. Yorik

    Dropbox support told me the new 1.7 version should fix this problem: https://forums.dropbox.com/topic.php?id=95594

  17. Ross

    I do have a linux ext4 machine attached to my dropbox, so wandered if that could be part of the problem. I tried disabling sync on that machine and uploading a new photo from the blackberry, but it still appears as a zero size file (checked using the web interface).

  18. Yorik

    I'm experiencing exactly the same bug (installing dropbox on a new pc, on an ext4 partition on a brand-new HD), a lot of files have been "wiped" during the restore process and have 0-byte size... Contacting Dropbox now, I hope they can restore them for me... It's pretty scary...

  19. Ross

    I'm experiencing a variant of this bug at the moment. I added a blackberry phone to my account and started using the photo upload feature of the official app. The first photo worked fine, but every one since appears as zero size with no history (even though I pay for the unlimited undo "packrat" feature). Thankfully the photos are still on the phone because unlike a desktop, it doesn't continuously sync with the servers.

  20. Laura

    I "restored/fixed" my 0-KB folder.

    1.) Paused Time Machine 2.) Increased my Dropbox storage quota from 200 to 500 GB 3.) Added Packrat feature 4.) Removed ALL Windows-incompatible characters from my file names: https://www.dropbox.com/help/145/en I don't know how, but my files are back in my folder and synced. I use Dropbox 1.4.7 - synced between MacPro & 2 PCs I typically download RAW files from my camera to my desktop, edit, then drag into Dropbox. I noticed the O-KB folder sometime after importing via 'Camera Upload' feature. This feature may or may not be involved in 0-KB error. Good Luck!

  21. shadow land

    ZFS

    ftw?

  22. dgw

    I ran the command in msysGit's Bash shell and found a bunch of zero-size files. Most of them are system/application files that are expected to be empty, but a few files transferred from a college FTP server appeared in the list. At least one of them was zero-sized at backup; that page on the website is completely blank. While my results don't confirm this bug, they are odd, as I haven't noticed those zero-sized files since they were backed up from the FTP server two years ago.

  23. stefan

    I had the same issue (files zeroed out). I'm mostly using Dropbox on MAC, and it seems it was a rarely used Linux (Ubuntu) Dropbox client that zeroed out the files.

    Some of them I could recover (I realized fast enough), but for others I realized too late in order to try and take advantage of Dropbox's 30 days history.

    Until the issue is understood I will run a daily cron job that looks for zero files and emails me if it finds any.

  24. elGuapo

    Why are you relying on your "precious" files sitting on someone else's free service? 1 version sitting on DropBox is not a "backup" by any stretch of the imagination. "Backup" means there are 2 copies in 2 different locations.

  25. Florian Harbecke

    You Should try adding -type f option to only list files. Directories are always 0 byte ;)

  26. Vic

    If you're using cygwin, the find command you cite seems to return all directories too for some reason. Fix this with

    find /path/to/your/Dropbox -size 0 -type f > ~/Desktop/zero-byte-files.txt

  27. G. Cohen

    Just a quick note, Time Drive (https://launchpad.net/time-drive) is a GUI front-end for Duplicity, if it helps. I'm not affiliated with Time Drive, just used to be a user (but not anymore, for reasons not related to Time Drive itself).

  28. StopTheMadness

    STOP with the EXT4 bug madness. The person who reported the EXT4 bug had turned off several safety knobs (ie: non-default settings) and used umount -l and other bad practices. Does Dropbox change EXT4 mounts to nobarrier and journal_async_commit and do forced shutdowns with lazy dismounts? No? Move along then.

  29. clasqm

    Just a small note: If you run the find command as directed here on a Mac, you can ignore any results like this:

    /Users/clasqm/Dropbox/Family Documents/Icon

    That just means you've put a custom icon on that folder and that is supposed to be a zero-byte file.

  30. Daniel

    A possible reason why DropBox doesn't have file data for the changes is that the modified time for the files may not have changed. i.e. when the files were zero-bitten DropBox detected the change, then overwrote their most recent entry with the zero-byte version. It's not hard to believe that DropBox use the last modified time as some sort of key in their data structures.

    I've performed the aforementioned test on my computer and have come up with a whole lot of zero-byte files as well. However, I recognise these as all being files that I copied from a Linux computer onto my Mac (Snow Leopard), then into my DropBox (I've never had DropBox installed in Linux).

    It's hard to say exactly where and when these files became zero'd but DropBox seems to think that they have always been zero'd. Possibly there may be an issue with DropBox syncing files that have been "touched" by Linux - hard to think what but these days with extended attributes and such it cannot be ruled out quite so quickly as in the past.

  31. Bug

    The reason I'm confident that this bug is not due to filesystem errors on my machine's part is because Dropbox's version history for these files has become corrupted.

    The thing is, Dropbox should be informing YOU of this, instead of you having to do their job for them.

    Official line: "Nope, no problem on our end."

    Expert user: "Your internal metadata is corrupted."

    (Silence)

    What is an ordinary user supposed to do?

    A backup service needs to actually ensure the integrity of their OWN data, not just plop an extra copy of your file in a single place until the bits rot. De-duped, of course, meaning one bad block can take out tons of files (say, a JPEG header block).

  32. SubmarineDeckhand

    I have found when I drag and drop any files that they are actually moved and NOT copied unless I make a special effort to ensure the CTRL key is held down on the drag & drop

  33. SubmarineDeckhand

    I have often wondered about this; never happened but whenever I link a new machine to an account there doesn't appear to be any guaranteed way to optionally select which is to be taken as master in the syncing process the online folders or the new box?

    It is similar with ipods if one isn't aware & careful any work to modify an ipod is lost as soon as it is hooked to a usb port with itunes installed; only option, after much searching first is itunes is master and u can say yes or no to sync. so u have to say no, then use 3rd party s/w to dump ipod contents then copy into itunes and then allow resync.

  34. Techload

    I'm going for a double backup solution now. Thanks for posting this.

  35. Eric

    Matt,

    Thanks for posting here. The reason I'm confident that this bug is not due to filesystem errors on my machine's part is because Dropbox's version history for these files has become corrupted. If you read over the details and correspondence, you'll see that Dropbox engineers were able to recover two of my files that Dropbox's version history had reported as only having a 0-byte version. These files were edited recently, within the 30-day window that all Dropbox users, Packrat or not, have version control for.

    The files had clearly been whole when first synced to Dropbox, but that version was not listed in Dropbox's history, and so I had no power to restore them. Even if my own disk had spontaneously 0-byte'd those files, this should not have caused Dropbox to lose the ability to restore it to its original version.

    More circumstantially, others are reporting similar issues:

    https://twitter.com/dangillmor/status/261921738441515009 - https://twitter.com/pc1oad1etter/status/261957001234505728 - https://twitter.com/frr149/status/261957708746469378 - http://news.ycombinator.com/item?id=4704236 - http://news.ycombinator.com/item?id=4704178 - http://news.ycombinator.com/item?id=4704063 - http://news.ycombinator.com/item?id=4704485

    It's tough to tell from these small updates whether these users had their files 0-byte'd only locally, possibly by the ext4 bug, or whether they've also verified that it's not recoverable from Dropbox.

    In addressing this bug report, please specifically address Dropbox's loss of version history. The two files that Dropbox engineers recovered had their version history wiped within the 30 day window.

  36. Matt Holden

    Hi Eric, (I'm the PM for the Dropbox desktop client team.)

    I just wanted to let you know that we take any claims like this really seriously. There aren't any known bugs on the Dropbox side that would cause this, and unfortunately there are potential causes such as hardware errors, filesystem corruption, and other OS issues (including those like http://www.phoronix.com/scan.php?page=news_item&px=MTIxN...) that can corrupt data or create zero byte files.

    Nevertheless we will continue to look into this just to be sure, and we also work hard to find ways for Dropbox to shield users even when the OS, disk or other components fail (our undelete/file revisions and Packrat are among these).

    Thanks, Matt Holden

  37. Eric

    @Nodovitt - if you're on Mac or Linux, run the command I listed above:

    find /path/to/your/Dropbox -size 0 > ~/Desktop/zero-byte-files.txt

    Replace "/path/to/your/Dropbox" with the actual path to your Dropbox.

  38. Eric

    @idont - Dropbox's own website dropped the older versions of these files, that it once had on record, so the issue could not just be my disk. Dropbox's engineers were able to manually recover two files from their servers that, according to the website frontend, didn't exist in more than 0 byte forms.

    @stacy, @scain - I don't use Dropbox for backup of all my things, and not my most precious/personal things. For those, I back them up myself to my webserver, though I haven't set up an automated system to do this. (I'm looking at duplicity (http://duplicity.nongnu.org) to do this.)

    @Kelso - I do have deleted file recovery enabled. For 23 files, I was able to use this facility to restore them myself. For the ones that are lost, their entire version history is just one, 0-byte version.

    @JohnB - Glad you were able to catch it. Feel free to reference my account by email (konklone@gmail.com) if you want.

  39. Nodovitt

    How do you check if the files are missing?

  40. JohnB

    Nice catch, and thanks for sharing! I checked my own Dropbox content and found a good 20+ files suffered the same fate. I had redundant backups of almost everything, so I don't believe anything was lost. This time. I submitted a support ticket to Dropbox with my information. Hopefully it will help them resolve the issue.

    I sync my data between two computers, a Win7 machine and a Lubuntu laptop. The laptop selectively syncs just a few folders, but all of the corrupted files were included in that list. Not sure if the same is true for anyone else, but it's more info for the Dropbox folks to chew on.

  41. Kelso

    Pack Rat Dropbox extra subscription allows you to recover any deleted file, regardless of when it was deleted, would it solve the issue?

  42. scain

    I use Dropbox for synchronization among different machines and it is great for what it is. However, as you've discovered file synchronization is not a substitute for a good backup. I personally use CrashPlan for automated backups because it works on Windows, Linux and OS X and is well worth the price ($0 if you back up to your own devices).

  43. stacy

    I assume Time Machine or some other incremental backup solution would be a good supplement? I am hard core about backups since losing some photos of my kids years ago.

  44. idont

    If sectors are damaged on your disk, this can happen... If the source is corrupted, the offsite backup can not fix it. I lost a few familiy pictures because of this... :( Since that mini-drama, I only use minimum RAID 1 configuration where my files are stored + I use offsite backup (mozy).