Dropbox: Can It Change My Files?

Mystere said:

Use a tool like https://www.boxcryptor.com/en/

Not only does it prevent anyone from accessing or changing your files (if they're not on your local PC), but it encrypts them as well. Because the encryption happens on your local PC, all DropBox can see are the encrypted contents.

nice, will it work for my pc (only my pc) or my dropbox account?

plus, will it work only for me even after a clean windows install?

I've never used it myself, so i can't tell you with any certainty. I can tell you that DropBox themselves will only see encrypted data, though I believe you need their professional version to encrypt the file names as well.

You have to be careful with encryption though. If you do a clean install, you may lose the encryption keys and your data becomes useless to you. You need to back up those keys on a local USB drive or something. If you have the keys backed up, then you can get access to those files again after a clean install.