I need to run an older version of Avid video editing software (that will run on OS 10.7 and lower) on a MacBook Pro (probably mid 2012). I have an original Apple DVD of OS 10.7 from a previous computer purchase. I get the circle with a diagonal line through it whenever I try to load the 10.7 OS. I've tried directly loading it and using recovery mode (CMD + R) after erasing the drive with disk utility tools.. I've talked to Mac tech support three times and have been told "officially" that Apple does not support downgrading and that 10.7 will not run on this machine (10.8 was shipped with this machine). "Unofficially" I've been told that there is a workaround but they can't discuss it. I haven't found the solution online. Can anyone point me to information/guide for downgrading a MacBook Pro like mine? I would appreciate any assistance? Thanks. Dan.