I bought the 27" iMac 3 days ago. Tranferred Mavericks and all my applications, user profiles and files to it from my previous 27" iMac 2011 model. Yesterday night my new Mac experienced a complete system lockup and I had to press the shut down button to close it because everything was frozen. At the time of the lockup I had Firefox, iTunes, VLC and Skype open. I checked the log files for a crash report but there wasn't any! After the force restart I opened Activity Monitor to check everything and even performed an Onyx Repair Permissions! Is there anyone with lockups on new iMacs and how can I resolve this issue?