I've got a 21.5 late 2012 iMac. Mavericks has been on it for about a week, and I've had to restart the computer from the power button about 10 times. I cant put it to sleep, because sometimes it will wake up, then freeze when I unlock, or sometimes it just won't wake up at all. It has lots of weird window placement bugs too, like when I wake it from sleep all the windows are in the top left hand corner and they won't move out of there unless I restart. Then theres the fact that I cant run my iMac under anywhere near the same kind of load that I could before. Right now I have 3 safari windows open and 10 apps and this thing is running like a dog, literally stuttering all over the place and barely useable, would run beautifully with the same load on ML. Any way to solve these bugs or am I just going to have to roll back to ML? The only reason I installed Mavericks (well the main reason) was iCloud keychain, and the 'decen't' syncing of my pages and numbers files, between devices, but I'm not putting up with an OS that cant handle things or that freezes when I unlock my computer.