I am sorry for not getting back after your detailed response. ' for about three years, but I gave up on that.) (Also, the Dropbox icon has been stuck on 'Starting. I can't search my email because my computer is stuck with Dropbox syncing. I pay something, I am not sure what level that is. ) I do have a lot of files (300Gb), I use this for work.

Is there anything that can be done to improve this? (I use selective sync as much as possible. Or at least, it does so with way more files than are actually in need of syncing. It seems to me that Dropbox simply downloads and uploads every single file if it thinks something changed. Yet, the whole sync circus started again. Just now, I know for a fact that *nothing* changed in my files between the time I logged out and then logged back in after ~1 hour. I am pretty sure it is Dropbox, because the disk crunching and the slowing down goes away if I turn off Dropbox (or just the sync). My desktop mac (older, but running High Sierra, 32G memory and decent disk space) becomes almost unusable for 10-15 minutes following startup. I am sorry, I don't see how this answer solves anything.

Instal the new for mac Lies of P