Just bought a new 3TB My Book and tried to make a back up from Windows 7 and it failed showed Error Ox8078002A which said that I had to re format the drive which I did but now have 1.99 Tb of space
Same thing just happened to me. I bought a 4TB drive. Because I have Windows 7 I followed the directions telling me I had to reformat with Windows. Did that and only have 2TB.