I am a huge fan of Dropbox, but every once in a while the Dropbox application on my Windows-based PC and Mac gets caught in an endless sync loop in which no files are actually being downloaded or uploaded, but the application is running like crazy to catch up.

This happened most recently when a video being shared between myself and several coworkers needed to be re-rendered and replaced. As the replacement was rendered, the file in the host’s Dropbox folder seemed fine, but the rest of us were caught in an infinite sync cycle in which nothing was actually being downloaded.

This problem was caused by a conflict in Dropbox’s cache. Because a file with the same basic name and properties already existed, Dropbox wasn’t able to create the new file on our end. This isn’t always a problem, but it can be if the sun and moon are aligned in a certain way.

Either way, you can solve these issues almost every time by clearing Dropbox’s hidden cache folder. This folder holds gigabytes of miscellaneous data collected during file downloads and sync processes in a series of smaller files with crazy alphanumeric names. This folder should reset itself every three days, though in cases where your Dropbox application is experiencing a conflict, you may not want to wait for the problem to resolve itself.


Deleting your Dropbox cache can free up plenty of disk space and resolve sync issues. Doing this on Windows is actually a pretty simple process. All you really need to do is delete all the files inside the cache folder (but not the cache folder itself). Once this is done, you’re free to empty your Recycle Bin and go about your day.

Here’s how:

  • Select Start > Computer to launch Windows Explorer.
  • Navigate to your Dropbox folder.
    • You can usually get there by pasting this in the navigation bar:


  • Select all by pressing Ctrl+A.
  • Press Delete and confirm if it asks you if you’re sure.
  • Give Dropbox a moment and check to see if the issue is resolved.

At this point, if all is well, you can empty your recycle bin.


Deleting your Dropbox cache on OS X is very much like it is in Windows. All you really need to do is find the hidden cache folder and delete the contents. Here’s how:

  • Open Finder.
  • Select Go to Folder… from the Go Menu.
  • Type the following in the field:


  • Select all by pressing command+A.
  • Drag the files to the trash bin or right-click and select Move to Trash.
  • Give Dropbox a moment and check to see if the issue is resolved.

At this point you can safely empty the trash bin.


Deleting your cache files in Linux is easier than doing it anywhere else. All you have to do is open Terminal and type the following:

rm -R ~/Dropbox/.dropbox.cache/*

That’s it. You should be all set from there.

Computer/Network Issues

Not all sync issues are caused by conflicts in the cache. Some of them may be the result of problems within your own network, or your computer.

If wiping out the cache doesn’t clear the jam, you might consider quitting the Dropbox application and relaunching it. Should that fail to work, rebooting your computer would be a reasonable next step.

If you’re still experiencing issues, you may want to investigate further to see if the ports Dropbox is using are in conflict with other applications and/or systems on your network. You should be able to run Dropbox on a dozen or more systems simultaneously without any port problems, though your router may be blocking the application from passing through should it detect a problem.

You can also check for any faulty proxy settings by right-clicking the Dropbox icon in your task bar, selecting Preferences and choosing the Proxies tab. For most people, you’ll want to have it auto-detect your proxy settings. The vast majority of home networks out there don’t run through a proxy. This is usually a tool implemented by enterprise-level IT.

Make Sure Selective Sync Isn’t On

Selective Sync is a feature of Dropbox that only syncs certain folders within your Dropbox account to the computer. There have been times when I’ve forgotten I had that on, and wondered why a specific folder wasn’t appearing in my PC’s directories.

To check this, right-click on the Dropbox icon in your task bar and select Preferences. Once there, head over to Advanced and select Selective Sync…. Make sure the folder you want is checked.

Rename the File/Folder on the Website

One trick to resolve sync errors I found is renaming the problematic folder through the Dropbox website. For some reason, a simple renaming of a file and/or folder can make everything suddenly start working. I don’t know why, but it has fixed the problem for me in almost every case.

You can do this by going to Dropbox.com and navigating to the file/folder that appears to be experiencing the issue. Once there, left-click the folder or file and select Rename from the menu. Even if you’re just adding a number or letter to the end of the filename, it should fix your problem.

Additional Notes

Your Dropbox cache will probably begin filling right back up the moment you empty it out. That’s perfectly fine, especially if you’re downloading files which have been suddenly made available to you after clearing up whatever was clogging the tubes. The important thing is that the infinite loop is gone and files are beginning to upload/download normally once again.

This problem usually resolves itself after three days, so clearing the cache is rarely an absolute must. Still, it’s good to know you can fix issues right away and get back to work should you be facing deadlines.

Dropbox is one of the few collaborative sync solutions out there that works on virtually any desktop operating system out there. This makes it a great solution for content creators working on collaborative projects. Occasionally, problems like these will present itself, but it’s always good to know how to resolve them and get back to work with as little hassle as possible.