“My files are missing! How do I get them back?” https://www.dropbox.com/help/969/en (Dropbox Help Center)

“Q: How do I recover deleted files? A: You can recover any file deleted in the last thirty days from the Dropbox website.” https://www.dropbox.com/help/296/en (Dropbox Help Center)

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Hey nclod,

If you are still having an issue, you can email me directly at graham (at) dropbox.com i'll do my best to help.

Graham Dropbox Support

Are you sure you don't have any local copies of the files? Storing your only copy of your PhD thesis at a third-party seems quite short-sighted.

Sorry to hear about the loss. I hope you can get your files back.

EDIT: I've not used Dropbox. I gather from gokce's comment that you did have local copies, but Dropbox deletes them when they are deleted from Dropbox. That's unfortunate.

The copy of the file that Dropbox stores in your local file folder is NOT the same thing as a local copy. That Dropbox folder is under the control of Dropbox, not you. If you want a local copy of documents, then put that copy in some other folder. Yes, this means that you will have two copies of the document on your hard disk and that may seem redundant but just think, redundancy is the same thing as backup. So be redundant.

In fact it would not be a bad idea to keep many extra copies of an important document like a PhD thesis as it evolves. Either install and use a revision control system, or just save a copy every week with the date added to the filename.

If you can't recover them from dropbox a tool like recova (http://www.piriform.com/recuva) might be able to recover them from your hard disk (when a file is deleted it isn't really erased, just a pointer gets deleted)

Also, did you try checking the Events history in Dropbox? Sometimes old files are in there.

since dropbox files are also stored locally it is possible that the files are still on your harddisk somewhere but unlinked. if that's the case I suggest you turn off your computer right away and see a professional.

If you have some technical savvy, try http://extundelete.sourceforge.net/ for ext3/4 filesystems, http://ntfsundelete.com/ for NTFS.

If you're using something other than than one of those two filesystems, you should probably know how to handle this yourself.

You left out HFS+, OS X's file system.

However, Dropbox on OS X has a cache file at ~/Dropbox/.dropbox.cache – so if OP uses a Mac, chances are he won't need an undelete utility.

More info: https://www.dropbox.com/help/296/en

Never trust the cloud. Never trust local storage, either. Never trust any one thing to keep your data safe. Keep multiple backups at multiple locations of anything really important.

While you are at it, print all your data using Paperbak[1] and store it in your attic. Make a few extra xerox copies and distribute to friends and family.

[1] http://ollydbg.de/Paperbak/

I don't know much data OP wants to backup, but using Paperbak you can backup 250MB to 1.5GB per ream of paper. That gets out of hand real fast.

It does remind me of how PGP used to be exported out of the US, due to government regulations: http://www.pgpi.org/pgpi/project/scanning/