I was recently working on clearing out some space on my hard drive. I had some large files in Dropbox that I wanted to keep in Dropbox, but no longer wanted to sync to my computer. I went in to Dropbox and created a new folder that did not sync to my computer and moved the large files into it. As my computer synced with Dropbox, the files were removed from my computer, but I did not see any space freed up in my hard drive storage.
I did some digging and discovered that Dropbox stores a cache to help with logging and with undo-ing accidental deletions. This means, however, that when you delete something, it is not gone right away. This cache stores things for approximately 3 days, but if you want to get rid of things sooner than that, you can manually delete things.
To do this, you will need to be able to view hidden folders (directories) on your computer or access the hidden folder directly by its path. On my Mac, I have hidden folders displayed, so I just opened Finder and opened my Dropbox folder. In that folder, there was a hidden folder named .dropbox.cache. Inside that folder, I found many other folders, but the two most important ones were labeled with today’s date and yesterday’s date. In it were the large files that I had removed from syncing with my computer. I was able to click on them and drag them to the Trash manually (or use a keyboard shortcut to delete them, like Function+Delete), empty my Trash, and the space was now free on my hard drive again.
If you do not have hidden folders visible on your Mac, you can access the cache folder directly by opening Finder, clicking on the “Go” menu, and choosing “Go to Folder” (or clicking on Shift + Command + G while in Finder).
If you are using Windows instead of a Mac, you can do the same using Windows Explorer. The .dropbox.cache folder is inside your Application Data directory or you can access it directly by entering “%HOMEPATH%\Dropbox\.dropbox.cache” in the Windows Explorer path bar.
If you are using Linux, you can access the cache folder via Terminal at “~/Dropbox/.dropbox.cache/”.
For more information, see the Dropbox documentation at: