Dropbox seems to be running really really slow and since it's how I share files with a co-author it's causing big problems. I rebooted my computer and it took about 20 minutes for Dropbox to finish "starting" and then it indexed and syncced in a pretty standard amount of time. I made change to several files and they haven't syncced yet. Under "recent files," the last synced file was 45 minutes ago.
I'm on a MacBook Pro running 10.11.5 and running Dropbox 21.4.25. I have no limits on the bandwidth and a speed test shows my current download speed at 230 mbps and upload speed at 15 mbps. The files I'm trying to sync are Scrivener files made up of individual txt files (so it's about 714 txt files). In the past a sync like that would take a couple of minutes max.
I have two Macs that are linked to the same Dropbox account and I use Dropbox to keep the files synced across the two computers so I can work on a file, close it, let it sync, and then my co-author can open it and work on it, etc. We've had to resort to emailing the file because the syncing is taking too long.