Hi, Checking MacTracker I find the largest drive from Apple was 500 MB but that should not preclude your using your current drive. The only thing I did find is a firmware update--EFI firmware update 1.7. You might want to check and see what level firmware you have--it MAY help with your problem but there are no guarantees. If you do decide to update read the instructions carefully-- a firmware update can brick a logic board. The easy answer is to install a 500 GB drive and put your 750 GB in an external case and download your finished edits to it to insure room on the system drive. Good luck. Anyone with a better answer please speak up.