I'm getting the same error as well. When I go to load the VM the partition disappears from the desktop for a split second, then reappears and pops me the message again. Though, I am trying to do it with Vista, so I'm betting that's where my problem is since I can use a different partition, a FAT32 partition, as a real drive with my XP VM I know its not a problem loading partitions, it is specific to my Vista partition. Though, any thoughts, tips, hacks will be gladly explored. I should also note that my NFTS Vista partition can't be unmounted without being done with a sudo via the command line. I only show as having read permissions on the partition. I thought NTFS was read only due to licensing limitations, not due to permissions... or is permissions part of how the licensing is kept in check? I dunno, I just thought it was weird that I needed admin privileges to unmount the partition.