MacPro 8 Core 2.8GHz, OS 10.5.7, 8GB RAM Parallels 4.0.3844 Additional internal 500GB HD single partition (entire disk) Windows XP Home NTFS format Boot Camp into Windows works without issue so there appears to be no obvious issue with the Windows OS. In Mac OS Start Parallels Desktop black window opens and gets to Trying to boot from Primary Master IDE drive . . . Error loading operating system_ I installed Parallels a few days ago and it worked without issue. Recently I got the Unable to connect Hard Disk 1. Now I'm getting the above error. I don't see any clear way to trouble shoot or fix this issue. I'm not sure what caused it either so I'm not sure what to do to prevent it from happening again.