@papadimitriou No need to actually uninstall. If you go to the Preferences window and click on the Reset tab, there is a button to reset and quit the app. Then start the app again. Unfortunately, re-index is then needed, which may take a while if you have lots of files. Anyway, hope this helps!
@Arius123 Sorry for not responding sooner. The short answer is Yes, due to Dropbox API change. See https://t.co/NloTEzWbGO in particular point 3 on the most recent post (January 18, 2018).
@ricburton ...you can use "RevisionsAlt" to run a second instance of the app, to monitor a second account. See https://t.co/M1xKMHkdkk Hope this helps!