Why won't my 3TB or 4TB external drive work with Microsoft Image Backup in Windows 7?

Windows Image Backup in Windows 7 will not support any GoFlex drives that exceed 2.1TB (3TB and 4TB models) or older model Expansion Portable and Expansion Desktop drives (models pictured below).
 Portable Desktop


As an alternative to Windows image backups for Backup Plus drives, GoFlex drives, and older model Expansion drives, consider using DiscWizard.
For Backup Plus and GoFlex drives, the bundled software will allow you to back up your data.
Microsoft only supports drives that are set up to use 512 byte blocks as destinations for image backups. The drives listed above are compatible with all other Windows functionalities.
To allow 3TB and 4TB drives to work in older operating systems such as Windows XP, these drives are configured using 4K byte blocks. Microsoft has added support for 4K drives in Windows 8. See here for more information.
Newer model Expansion portable and Expansion desktop drives (models pictured below) are compatible with Windows image backup. For more information about the limitations of Windows Backup and Restore, please contact Microsoft.
 Portable  Desktop