I have an intel mac (macbook) with a fresh (not upgraded) copy of Leo. Apparently this does matter, as Tiger would have been able to mount the disk with no problem so I suspect that ability remains in the computer when upgraded (only a suspicion). I have been trying for 3 days to get my Canon solutions disk (14.3) to mount in Leopard. When I insert it, it just spits back out after spinning up. Canon support had no idea what to do, and apple wasn't giving me any help since it is a third party app, they simply sent me the direction of canon for a fix. Thankfully I figured out a solution. This should work for all who have disks that will not mount and spit back out. As a last resort right before I pulled my hair out I decided to try and force the disk to mount by holding the shift key while inserting the Canon Solutions disk. IT WORKED! Do not let go of that shift key until the disk is mounted completely and the installer icon is on the desktop. Once it is mounted you are good to go and it installs with no problem. I hope this information can help some of you having this issue.