o its imposible? i just wanna leave main client on the SSD
its better for performance, loadcreen, you know
and test 1.6 PTS from my HDD drive...
But that's exactly what you wanted. You copy(not move) the whole game directory to a HDD. Enable PTS on the copy. Play PTS from the copied directory. Play live game from the original SSD installation.
The easiest way to complete this is to download the launcher from the account website at Account.Elderscrollsonline.com and install it to the alternate hard drive. From there, open the launcher and install PTS as your normally would.
This means that you'll be running two different versions of the launcher, but you'll be able to keep the content separated by hard drive .