I have three large hard drives in an external USB enclosure - one 1.5TB formatted as NTFS, and two 1TB both formatted NTFS (I think). All three disks worked perfectly under Vista and, from time to time, on a Mac I also use at home. I recently upgraded my PC to Win7, and suddenly, two of the HDD are no longer available for use. I go to My Computer>Manage and select Disk Management, and the disks are there, but the each show a 200mb EFI partition, then the 931gb (Health) Primary Partition - but all of the options are grayed out on both drives. I have a ton of data on these that I intend to keep; is there a fix for this problem, or do I need to uninstall Win7 and go back to Vista? Thanks in advance for your help.