The major change with this rewrite is the support for the mount manager. Fstub will now assume that most of the devices are PnP and that they are already registered to the mount manager. It will thus ask the mount manager to assign the drive letter. Fstub will keep assigning drive letters non mission critical devices such as CDs, floppies and other removable devices. See MountMgr:QueryPoints API test that will now return mount points :-).