Found this on the Western Digital page. Trying it now will let you all know if it works or not? Fingers crossed
Error: 0x8078002A occurs when backing up to a 2.5 or 3.0 TB drive in Windows 7 Backup and Restore
When using Windows 7 Backup and Restore with a 2.5 TB or 3.0 TB drive, the backup fails with an error code of (0x8078002A).
This problem is caused by an issue with the Windows 7 Backup and Restore utility when using drives with 4K Logical sector sizes, which are found on WD 2.5 TB and larger external drives. This is different from an «Advanced Format» (AFD) drive which use 4K physical sector sizes. AFD drives should not cause this problem.
It is still possible to use a 2.5 TB drive or larger with Windows 7 Backup and Restore, as long as you don’t need to use the drive with Windows XP. Using the WD Quick Formatter tool, select the Factory Default configuration to reformat the drive.
Warning: This tool will erase all data on your drive, so take the necessary precautions.
After formatting the drive to Factory Default mode, the drive will be usable in Windows Vista and Windows 7. However, the drive will not be recognized in Windows XP. This is the only way to get Windows 7 Backup and Restore to work correctly.