I used the default settings for this program and executed a clean-up operation. Ccleaner proceeded to delete many temporary files. Unfortunately, "temporary files" is exactly where Parallels (http://http://www.parallels.com/) stores its data files. In other words, ccleaner destroyed my Parallels virtual machine.
The specific folders that Parallels use are in /private/tmp. For example, my virtual machine is for Windows 7 with three disk partitions C: D: and E:. Parallels places the disk data in three directories
/private/tmp/483/C
/private/tmp/483/D
/private/tmp/483/E
The number 483 changes often. I don't know if there are other important files in /private/tmp. Believe me, the three folders that I have listed are important.
I hope that you find this bug report to be useful.