Two different USB 3 HDD docks - disk partitioned on one not usable on the other I have two different 3TB SATA hard disks:


a Toshiba DT01ACA300
a Seagate ST3000DM001.


I also have access to two different USB 3 HDD docks:


a Connectland DOCK-CNL-YJK3519-V3+ES
a Focus SATA + IDE dock (exact model name unknown)


It turns out that if I partition a disk on the Connectland dock as GPT with one HFS+ volume, the disk would become unusable when I plug it onto the Focus dock; OS X Yosemite would complain that the disk cannot be read and suggest that I initialize it.

Same thing the other way around: if I partition a disk on the Focus dock, the disk would be unusable on the Connectland dock, and OS X Yosemite would complain that the disk cannot be read and suggest that I initialize it.

This happens to both Seagate and Toshiba disks.

In both cases, the disk would be recognized as a 3TB disk. I can also use the full capacity of the disk, provided that I put the disk on the dock where it was partitioned and formatted - i.e. if I partitioned and formatted a disk on the Connectland dock, I would have to keep using it on the Connectland dock.

What's going on? How is this even possible? How am I even supposed to shop for a new dock reliably if my dock dies?
The problem will lie with the dock disk-controllers and the method they use when translating the hard disk layout. I recently serviced an HP NX7400 laptop and the BIOS has two different modes for dealing hard disk translation - LBA Assist and Bit-shift. 

Both work, but if a drive is formatted using one method it will not be recognised if the other option is then selected after partitioning and formatting.

The acid test would be to format both disks, one on each dock, and then hook the drives up directly to a Mac. I suspect one of the drives will be recognised and accessible but the other will pop a "Disk Unreadable" message and prompt to be initialized.