As a matter of fact, I did have a problem with the MyBook being reported as only ~375 GB. But it wasn’t with Windows itself.
The current free edition of HD Tune (version 2.55) apparently cannot handle drives of this size. It reports the MyBook 3 TB as only 375 GB, and cannot perform any benchmarks. An attempt results in an error dialog stating, “Read error! Test aborted.” HD Tune Pro (non-free, trial edition) has no such issue.
I suspect the free edition of HD Tune can only handle MBR disks. The MyBook must be partitioned with GPT.
Once I get the new enclosure, I expect to have to reformat my 3 TB drive, using GPT, because it is presently (and silently) encrypted (this is one reason I’m dumping the MyBook enclosure!). So it will look like an “unformatted” disk to Windows 7.
Because I have a fairly old motherboard (2007 design), it uses BIOS instead of EFI. I suspect that I would be unable to boot from the 3 TB drive, due to its use of GPT rather than MBR. But that is fine, as the drive is only for backup, not OS use.
