Hi... Parallels; The PT Compressor will not work if a "Snapshot" is active. It takes a very longtime to remove a snapshot to run "the Compressor." Would you consider having the "Compressor" program temporarily move the "Snapshot" so the "Compressor" can access the drive info. This improvement would make it easy for the "user" to do disk maintenance, on the Vista drive, and save a lot of problems for the user. Thanks. DesertFalcon