Dropbox uses a ton of hard drive space despite most files being online only

Sorry to hear this, eroberts. Can you send us a couple of screenshots of what you see on your device (including the options you see when right-clicking on your Dropbox files and the size of the cache folder)? 

I’d also like to know the syncing status and app version of your desktop app.

I'm having the same issue on Windows, but this doesn't work. I had already previously cleared the cache. i don't see the option to make online only when I right-click, I only see manage hard drive space. Once I do this, Dropbox says successfully done, but it's not actually doing anything, because once I go back to manage hard drive space, it shows the space Dropbox is consuming as if I had done nothing.

Have you tried deleting the cache folder to see if this helps? Did you mark the entire Dropbox folder as online-only?

You might need to check the properties of each subfolder manually to see where the space is being used up.

Exactly, you have now understood the entire problem!  Where is all my hard drive space being used!

According to that image and the size on disk, the folder appears to take up just under 1 GB of space on your computer. Should the folder take up less than 1 GB of space?

In order to assist further, please could you directly right click the Dropbox folder itself, not individual files, then choose properties, and attach the screenshot showing how much the Dropbox folder is taking up on your machine.

All the files are still showing Zero Bytes on the C drive.  I can't believe it's just me with this issue.  It has always been this way with Dropbox.  

I quit OneDrive and the grey Xs are still there.  It made zero difference to the disk space.

Hi again, John! Can you please try quitting OneDrive instead, like Jay suggested? Do you keep seeing the grey Xs even then?

Are you still seeing 0bytes, even if you right click on the Dropbox folder directly, and go to its Properties?