HitmanPro only scans the boot drive, and not external or extra drives. This is due to the way HitmanPro is engineered. HitmanPro does not blindly scan your entire disk. Instead, there is an intelligent algorithm inside HitmanPro. We call the behavioral scan. It determines which locations on the disk should be scanned. Adding a disk from another Windows installation does not trigger this algorithm. Its contents are not related to the local Windows configuration.