Hello! I've seen this topic being explored in other places on the web, and I've tried all of the solutions I could, but I feel my situation may be slightly unique in that it only happens rarely. Anyways, here is my experience. I began having trouble when I was working in Logic Pro 9, and it froze. I don't remember exactly all the details, but I was able to force close it, and then it just wouldn't open again. I restarted the Book, and then when I clicked on the icon to open Logic, it bounced once and never opened. After multiple force closes and restarts to no avail, I decided to upgrade to Mavericks. Mind you, this was only a few weeks after I installed a new SSD - because very bad things were happening every day - and everything had been running so super smooth after the new hard drive install. So after installing Mavericks everything was fine, but I'm still finding that maybe once a month, this happends with the following applications: Logic Pro 9, Ableton Live 9, and Google Chrome. With Chrome, the logo bounces and bounces and will not open. It eventually stops bouncing. Now, all three applications won't work when one freezes and I have to restart. The other day I tried cmd-option-esc when Ableton froze (there was no mouse icon, and I could not three-finger swipe to another screen) and I was able to restart the application just fine. So again, if say, Logic freezes and I restart and it won't open, Live and Chrome are likely to also not open. iTunes, Calendar, Safari, all fine and will still open when the others won't. So I keep restarting and trying (sometimes during restart the blank white screen lasts for minutes before restarting) until eventually, after four or five minutes of the application not starting, it magically starts - and if I had clicked on another, like Chrome, to no avail, that starts up to. It's like there was a hiccup and everything caught up to time again and starts up no problem. When this happens, I always restart into safe mode, and every time, each of these applications works. I've deleted the cache from the library, I've done disk utility, verified and repaired disk permissions, logged out of Admin and back in, and a few other things. It seems to eventually work, but I use these programs professionally - and on stage. I'd like to get this worked out before it happens when it's super tragedy. I know I've typed a lot. I appreciate your time, if you've gotten this far. I'd be happy to answer any questions you may have. Thank you.