Edit: People in another forum are recommending repair permission/repair disc and a reinstall (and then maybe a fresh install if that doesn't work). That's what I'm going to try out tonight. I wish I could revert to Mavericks, but that seems like it may be a bigger pain than it's worth especially since I skipped over it, and hope that 10.10.3 (which may come out fairly soon) fixes some of these issues. If you have other advice, please still post! -- Hi! I updated my iMac, Yosemite from Mountain Lion, after getting a new iPhone 5s last week. I had to update iTunes, and to update iTunes, I had to update my OS. Specs in sig. Problems after downloading: - USB ports are intermittently working. - Illustrator CC will freeze my entire computer (rainbow beachball not even rotating). Happened twice already. Have never experienced a complete freeze before. - iMac turned itself off from sleep mode. After arriving home from work, the computer would not turn on. I thought perhaps I was having a power button issue (I've already had the shell replaced once), but after unplugging, waiting 15s, and replugging in, it turned on. I guess it's possible the power went out, but I doubt it. - Last night, it restarted from sleep mode after 5-10 minutes (freaked me out since I had gone to bed). I have read this is a common problem; surprised it hasn't been patched yet. I just turn it off now. - Every time something happens and I have to restart, my background is back to default. (minor gripe) I have done PRAM and SMC resets. Is it worth going back to Mavericks, or are these addressable problems? I thought since I had waited some time since release, the kinks would have been worked out by now (it's been 6 months, right?). If I was just using this computer for fun I wouldn't mind as much, but it's really messing with my freelancing work flow. If this has been addressed in another thread, please point me there, and my apologies.