I installed Mountain Lion on my MacBook Pro this morning. It got to the point where it said "less than a minute" and the blue progress bar was all the way over. Then it said "about a minute" Then "about 2 minutes" Then "about 3 minutes" Then it dropped all the way back to "about 20 minutes" But it finally completed and rebooted. It was a little flaky for a bit after rebooting in Mountain Lion. I restarted again and now it seems fine. But it scared me with that dropping back to 20 minutes. Anyone else see this behavior?