I installed 10.8.2 on my MBP 2012 yesterday. The update appeared to go on smoothly but it rendered OSX completely unusable. Within a few minutes of login the OS would completely hang, no error messages, it would just completely stop, mouse movement etc would cease and it would need a forced shutdown (using power button) to recover. This seemed to occur only when doing something with mac for instance clicking on download icon on dock or running hard drive permission scan. Has anyone else had this issue? I have had to restore back to 10.8 to stop it.