I was wondering if anyone else have resolved this issue or could help, I've searched the forums and couldn't find anything. I upgraded to Osx 10.10 about 2 days ago and after a successful complete install my mbp restarted and would not boot past the Apple logo and a 50% progress bar. I went online and found and done the following; pram reset, smc reset, single user mode dose NOT work, safe mode does NOT work, recovery mode works, I erased my hd and reinstalled from internet which automatically took me to Osx 10.10.2 and not to 10.8 which was my intention. I've turned off my WiFi after reading this could be a possible issue and still after hours and hours the boot stays at 50%. I'm running Mbp 2.66 GHz Intel Core 2 Duo processor, 320 GB hard drive, 4 GB RAM MC026LL/A Thanks to anyone.who can help.