I recently did an in-place upgrade of my Windows XP 32bit to Windows Vista and my secondary 750GB partition on my 3TB drive is no longer accessible. In Disk Manager I see it as an unallocated partition. I've tried reinstalling the GPT Loader but I receive the message "Ultra-capacity hard drive is already correctly recognized by your operating system. Additional driver installation is not required." and am forced to close out. For testing purposes I further upgraded the OS to Windows 7, but the same issue occurs. The main 2TB partition on the drive works perfectly fine. I know the data and the drive structure is perfectly fine on the secondary partition, because before I upgrade I made a Ghost copy of the OS drive (A separate 64GB drive) and if I put back in the Ghosted un-upgraded OS drive I have full access to the partition. Is there any way to force GPT Loader to install in Vista or Windows 7 so I can get access to this partition or some other trick to get it to recognize the partition.
AFAIK, the GPT Loader doesn´t work in Windows 7. You can use a 3TB disk as a data disk, not as a boot disk. The disk must be initialized as GPT.
I understand that Win7 natively can see the 3TB disk, but I already have 2 partitions with over 2TB of data that previously worked in Windows XP, I was hoping not to have to redo the entire 3 TB. I'm using a separate 64GB disk as the boot disk.
If I understand correctly, you have a 3 TB data disk and want to use it as a data disk in Windows 7. Is this an MBR disk? Or was it modified by the GPT loader so that is not MBR? If the disk is MBR, you could try to convert it to GPT. Supposedly, it can be done without data loss, but I´d create a backup first. There are several ways to do the conversion, see for example How to Convert MBR to GPT Disk in Windows 8 / 7. Also, some Paragon programs or Partition Wizard can be used. http://www.partitionwizard.com/help/convert-MBR-disk-to-GPT-disk.html.