If your Dropbox desktop installation experiences any of the following behavior, your Dropbox installation may be inaccessible or corrupted:
If Dropbox appears to sync files quickly at first, but then appears to be stuck at the last moment, it is possible your antivirus or system optimization application is interfering with the Dropbox application. This is a known issue with antivirus applications such as:
If this happens to you, consider adding Dropbox to your application's whitelist or try disabling your antivirus and restarting the Dropbox application.
TuneUp Utilities (Windows) is also known to optimize your computer by uninstalling Dropbox. If you are running TuneUp, try disabling the application and reinstalling the Dropbox application. You can report the issue with Tuneup using their online web form.
If you are not running an antivirus or are sure it is not interfering with Dropbox, your Dropbox settings may be inaccessible. If your settings are corrupted, one way to reset them is by unlinking and then relinking your computer to your Dropbox account. Don't worry, the files in your Dropbox folder will remain untouched.
If unlinking and relinking your account doesn't solve the issue, your settings may be protected or inaccessible due to a permissions problem. If this is the case, you can remove your settings by hand using an administrative account. Here's how:
icacls "%HOMEPATH%\Dropbox" /grant "%USERNAME%":(F) /T icacls "%APPDATA%\Dropbox" /grant "%USERNAME%":(F) /T icacls "%APPDATA%\DropboxMaster" /grant "%USERNAME%":(F) /T
icacls "D:\Dropbox" /grant "%USERNAME%":(F) /T
Note: We're working on a way to check and fix your Dropbox installation automatically from within the application. Stay tuned...