I used the dropdown menu from the USB icon in the VM status bar to select an external drive already mounted to the Host machine. I had expected that to eject the drive from the Host OS, and remount it in the Guest OS (both Lion in this case)... but after a long wait watching the spinning beach ball of death, and the Guest OS not responding to any key presses, I had to Force Kill the prl_vm_app process. After that, neither Host nor Guest, nor my other Mac were able to mount the drive at all. After running Disk Utility's 'repair disk' option several times, I was finally able to mount it read only (and enjoy 6 hours of copying 1TB of read-only files onto 3 smaller disks, reformat the corrupted drive, and copying everything back again). I'm now afraid to mount external drives to Guest OSes - from now on, I'll mount everything in the Host OS and use virtual networking to copy files into the guest. Is this a known problem? ETA for a fix?
