siliconman01 On both Vista and XP-SP2, the Registry Compactor is not compacting all the selected HIVES.
redseujac This can occur when those hives cannot be compacted (remember that from earlier discussions about that remark).
siliconman01 On two separate occasions, I selected all hives to be compacted with a system reboot at the end. It compacted 4 hives and then rebooted. I immediately ran the compactor again and it compacted 2 other hives.