I have spent half the day reading about, debugging and restoring my MBP because ML 10.8.5 totally hosed my computer. Numerous threads have been written about it and the problems it causes from drives going permanently to sleep, kernel panics, multiple software issues etc. This so reminds me of Microsoft's efforts for patch Vista..heaven help us all. Given all of the negative traffic on this board and Apple's support board I WOULD RECOMMEND EVERYONE TO NOT UPGRADE TO 10.8.5. This is, by far, the worst upgrade Apple has released since 2008 when I bought my first mac. A huge disappointment. Thank god I do backups.