The Dropbox app on Mac OS can't sync as it's saying my hard drive is full, when it isn't

Hi Stardrop, thanks for bringing this to our attention.

Could you attach a screenshot showing the error message you're seeing regarding the syncing?

This will help me to assist further!

Thanks Jay - there isn't an error message. Only that it's not syncing files that it shows as being "online." Please see attached.

When you click on the Dropbox icon on the menu bar, what is the current status of the app as it appears on the bottom left?

It is syncing, though it's not giving my any estimates or specifics beyond that. Hard drive space appears to be fluctuating... I've had to make other files online only to free up available space but I can't tell if the two files I need to sync are downloading or if other syncing is taking place. Very frustrating.

Could you try rebooting the Mac entirely to see if this helps?

I've rebooted a few times. That said, at this point, the issue appears to be resolved and I'm able to sync those two files. However, I'd love to know what is up with the discrepancy between "available disk space" and "disk space being used" under the "manage hard drive space" window. And if it's a matter of resetting the cache, how that would be done.

I'm glad to hear that the files are syncing normally now. 

There is a Dropbox cache folder which can be cleared, however, if you're on the File Provider version of the Dropbox desktop application, which is looks like you're on from the screenshots, there isn't a cache folder to empty.