I recently picked up 3x Hitachi Touro Pro 4TB USB drives. I hooked up 2 via USB to a Win7 SP1 x64 system - they come ready-to-use pre-formatted in NTFS with a single partition (with some free Hitachi backup software on it).
I copied 2-3 TB's data to each drive, all tested and working.
I then removed the drives from their enclosures (they are SATA 7k4000 Advanceformat (512e) drives inside the enclosure, with a USB-SATA bridge) and connected them to Z68 based motherboard (via onboard SataII ports). Setup as ACHI in bios with Intel drivers in Win7.
All 3 drives - included one that has never been connected via USB - all show up incorrectly. Disk Manager shows them as split into 3 partitions, 1st one is Primary/Active/RAW (with a drive letter assigned), next 2 partitions are Unallocated space. 1st partition is ~1TB, then 1.5TB for the two Unallocated Spaces.
The RAW partition is unreadable to Windows - which obviously wants to format the RAW partition, which I've not done. No request to initialise.
Some googling suggests I'm not the first to encounter the RAW partition issue after removing a drive from USB enclosure - some reports on large Seagate and WD drives, although every assumes it's become corrupt and needs recovery software to fix.
This is clearly not the case here - I'm assuming that either:
1) Win7/Intel drivers are not liking the 4TB partition information - although it's shown as 4TB drive in Diskmanager.
2) Hitachi set the drives up like this, the USB enclosure chip is performing some form of emulation beyond the official 512e standard (very unlikely) to present a NTFS 4TB partition
3) USB drives need less in the way of MBR/GPT info, and the drives are missing some key info here.
Any suggestions about what is happening here, how it can be corrected? Yes, I could delete and reformat - but there should be no need here...
More about :4tb drives moved usb enclosure raw unpartitioned space
The USB-SATA bridge firmware in Seagate's 3TB GoFlex externals and WD's 3TB My Books is configured with 4KB LBAs rather than 512-byte LBAs. If you remove the HDDs from their enclosures and connect them directly to a SATA port on your computer's motherboard, you will be exposing the drive's 512e sectors. You will still see the partition information in sector 0, but everything else will be in the wrong place.
You can confirm whether this is the case for your Hitachis by examining sector 0 with a disc editor. Compare the reported number of sectors inside and outside the enclosure. If you could upload the sector dumps, that would be very helpful.
You could also use Microsoft's FSUTIL to determine the physical sector sizes:
fsutil fsinfo ntfsinfo C:
Replace the C with the letter of the drive you want to check.