The GUID Partition Table does seem to have some limitations like UEFI based systems for the 64bit Windows only. Note this from the MSDN page seen at Windows and GPT FAQ
Windows Disk Support
Q. Can Windows XP x64 read, write, and boot from GPT disks? A. Windows XP x64 Edition can use GPT disks for data only.
Q. Can the 32-bit version of Windows XP read, write, and boot from GPT disks? A. No. The 32-bit version will see only the Protective MBR. The EE partition will not be mounted or otherwise exposed to application software.
Q. Can the 32- and 64-bit versions of Windows Server 2003 read, write, and boot from GPT disks? A. Starting with Windows Server 2003 Service Pack 1, all versions of Windows Server can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on Itanium-based systems.
Q. Can Windows 7, Windows Vista, and Windows Server 2008 read, write, and boot from GPT disks? A. Yes, all versions can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on UEFI-based systems.
With a pair of 1tb OS drives here one used for test purposes I was pricing 2-3tb for the extra space to store system images not OS a drive that size since where you back it up to? I know Seagate is working on a new coating for drive platters to reach a 20-60tb drive capacity. But that's still a ways off!
Here's one thread found at the WindowsServer site about problems seen when trying to create a full image from a 3tb drive. Unable to create system image on 3TB hardrive Windows 7-64 SP1
Another thread at the WindowsServer site may be a help for you there while that was for the 32bit 7 with SP1 when failing to see an image restored to a 3tb drive. Backup and Restore image fails 3TB Advanced Format Drive Windows 7-32 SP1
When going to restore any image the information is usually that the restoration tool will set the drive up to match the conditions which were seen at the time the image was created from the source drive. Size limitations of 2tb seem to get in the way as well as which mode the bios is set to as far as AHCI or Native iDE.
If your image was made while the 500gb drive was running in the AHCI mode and you now find you need the bios set for Native IDE that can bring up some issues as well as the size of the larger capacity drive getting in the way to some extent.