I had this problem this week. After doing everything that everyone said, RGB, trash prefs, new user, millions to thousands to millions, I looked at the color tab in displays (MAC System Prefs) there was no profile for the cinema display. I found that the ColorSync folder was not in the system drive library folder, just a number inside angled brackets. After copying this folder from another computer – rebooted and it worked.
Jim Townley
Television Production
Chattahoochee Technical College
Marietta, GA