Having installed from disc successfully yesterday, and also then played without problem for 4 hours, this morning upon launch I'm getting a 'disc authorization error' stating that they cannot verify that it's a valid copy. Having looked at their help section, the only thing I can think of is that CrossOver Games was conflicting with it (why now and not yesterday, goodness knows), and seeing as how I don't ever use it it has now been deleted from my MacBook. To no avail. If it was the CrossOver causing the problem, is there anything else I need to do to eradicate it/change settings to sort the problem? Many thanks if anyone's got any idea or solutions!