After you install it, when you get this message does that mean you can actually open the program again? This warning message should have been displayed the first time you ran your program before the re-installation. Well, if you can run photoshop now, then there is nothing to worry about. Follow Tihomir's advise, one thing to bear in mind is for best result, the drive ( whether physical or partition ) for scratch disk and your operation system should be different. Hope this helps a little :)