ref : https://www.softperfect.com/board/read.php?16,23674,23681#msg-23681
After unmounting WorkDrive you cant mount a Ramdisk on that drive letter because it wasn't correctly removed.
Actually Softperfect Ramdisk (before version 3.4.8 that was released after my report) would still try to create the ramdisk, then fail weirdly which causes BSOD on every bootup unless manually removed from the registry.