All I can tell you is that I've run Dropbox on my systems for a long time and never had it block startup or login. Are you running the latest version of Dropbox? If you are and the problem still persists, there may be a corruption present in the backups that's causing the problem. Have you tried reinstalling OS X?
Hi varjak paw,
It could be something else as I have not exhausted the possibilities... that said....
I have no problerm with Mountain Lion and Dropbox on my late 2011 MacBook Pro (a lab computer) with VM Ware Fusion/Windows XP and all sorts of geekie software for data acquisition and analysis. My 2010 MacAir (a personal computer) also runs dropbox and all sorts of software for photography and GIS/sportswatch with no problems. No problems with Snow Leopard computers either.
The problem is exclusively with the MacMini. I did initially have problems with the MacBook Pro but then I created a Mountain Lion flashdrive which cleared up all problems. But that was Mountain Lion before the latest software updates... ie OS 10.8.1. I'm running 10.8.2 on everything...
I'll probably have to do a clean install, but I really would like to figure out what the problem is so I don't have a recurrance once the MacMini's are up and running in the lab with alarmed students and assignment deadlines converging.
Try setting up another admin user account to see if the same problem continues. If Back-to-My Mac is selected in System Preferences, the Guest account will not work.General information.
I've not read of anyone else having this problem.
The screen freeze persists even when DropBox is not installed. The freeze at login appears to be a random but the second user account does not help as I cannot access it at login. I have also looked at permissions and the problem continues to crop up. I have not updated Mountain Lion on my laptop to 10.8.2 because I need at least one working computer.
I've heard from some other folks who have experienced the same problem, so for now I'm not shutting down unless absolutely necessary. This weekend I'll try a clean install. If that doesn't work, I'll be pestering Apple Support.
Thanks for the suggestions,
I think this is due to the daemon installed by dropbox app. See the following discussions:
I don't know what that daemon does. I think it restarts dropbox app when the OS is restarted. But it's buggy and can cause the OS to freeze at startup. Sometimes I may restart my MBP without any internet connection (for example, in a commerical flight). When I need to synchronize I can launch the app manually and let it does its job. So I don't see the reason why I need a daemon to do something unnecessary, and to make things worse, it gives me a headache.