My WIndows 7 desktop has a 75G SSD for a boot drive and a 1TB RAID1 array for a data drive. That's a lot of stuff to lose if your computer goes tango uniform. I've been hobbling along with a 1.5TB external drive for backups, but as my data drive fills up my backup drive is having difficulty keeping up. About once a month Windows will tell me that the backup drive is full (which is funny considering that I have the "Let Windows Manage The Space On The Backup Drive" option selected). So when Costco had a 4TB USB3 drive for $140 I was all over it.
I should have known I was in for trouble when it was a Seagate drive, though. I've never had luck with Seagate drives, and my luck didn't change in this case. At first things looked like they were going great. I unpacked the drive and plugged it in and it immediately mounted and started working. But the moment I tried to use Windows Backup I felt nothing but pain. The backup would run for a while copying files, but at the very end fail with I/O errors every time. Drop "Windows Backup 0x8078002A" into Google and you have a few days worth of reading to do. I mean there is tons of information on this subject.
Basically it boils down to Windows Backup doesn't work with the 4k sectors found in Advanced Format (AF) drives. I tried patches and re-partitioning and changing my disk label to GPT and creating two smaller partitions and sector alignment and on and on and on. On a side note I found that the drive came with a hidden 50G partition that required a boot into Gparted to blow away. I know that is a drop in the bucket compared to 4TB, but really, Seagate? Really? There are reports that Western Digital released a tool to reconfigure their AF drives to work with Windows Backup, but I cannot confirm those allegations and I suspect that they are false. All of the patches and workarounds thus far have been to get AF drives to work with Windows in general (as data drives), not to make them work with Windows Backup. Given that Windows Backup is more than just a simple file copying utility I don't see any of these hacks changing the fact that Microsoft has flat out said AF drives don't work with it. It sounds like Windows 8 and Windows Server 2012 are going to be the first versions to fully embrace AF.