Gigi can't install Photoshop because her "scratch disks" are full. Fortunately, for Gigi, Photoshop expert Burt Monroy is on hand to help out. It could be pointing to the wrong drive as a default disk. The chatroom found this thread from feedback.photoshop.com. The only solution there would be to install it on a smaller drive, but Leo says she could partition her current drive and install Photoshop to the smaller partition.