How do I remove Mountain Lion and reinstate the original server OS
I have upgraded to Mountain Lion on my MacBook Air, the problem was that my Mac mini showed it available on the apps store, which I then (Stupidly) downloaded. Can anyone tell me know how to turn back time and remove Mountain Lion from my Mac mini and reinstate the server OS as now the server will not operate correctly. - HELP!
Mac mini, iOS 5.0.1