I installed Virtual PC 2007 on Vista Ultimate 64.
The virtual machine is Windows XP.
When I decided to share one of the host drives (a USB2 attached 500GB drive), it does not allow files to be saved or changed on the drive from either the host machine or the virtual machine.
Even when the virtual machine is shutdown, access is only read-only. There are no NTFS permissions set, so I am completely stumped as how to get the drive back to normal read-write mode (as it was before installing VPC 2007)