I just recently purchased a a 4TB Backup Plus and installed about 1.5GB worth of data. I connected it using the USB 3.0 input on my motherboard. Works fine.
I then decided to use the bare drive itself, internally. So I took apart the external and opened it up. I removed the HDD and installed it in my tower. When I powered on the PC (Windows 8.1 Pro), and tried to open the drive, it gave me the:
This drive must be formatted, blah, blah, blah…
Then:
…the volume does not contain a recognized file system, blah, blah…
I’ve unplugged it from the tower (Desktop) and used the bottom adapter which housed the external drive and connected it using the USB 3.0 again and it works fine. It just won’t work internally using the SATA III ports.
The drive model is ST4000dm000-1f2168 and my file system is NTFS. When I first plugged it in using the USB 3.0, I did a full format.