Downloaded and tried to install .399 this evening. After disabling my antivirus and closing .398 (and *checking* that it had no processes still running), I started the installer. Each of 4 or 5 times I did so, the installation failed with an error message saying that jv16PT.exe could not be deleted.
Maybe I missed an obvious explanation, but I simply booted into safe mode where installation completed successfully. After rebooting out of safe mode, I tested Registry Cleaner (aggressive mode): flawless performance.
Christian Hart