[Solved] Hard drive enclosure docks

You omit some details that may be important.

What kind of dock is it?  (User guide and support site suggests that there are at least USB2 and USB3 devices, but I see mentions of Thunderbolt as well ...)

You have a drive ... -- but what drive is it actually?  If you have eliminated the possibility that your problem is drive-related in some way, and therefore omit that information, you may need to make that clearer. 

It will show up ... -- where? Windows? Mac? On any host computer?  Or only on a computer where the Goflex driver software has been installed? (Which seems to be PC and Mac only.) If it isn't installed or loaded, it may quite possibly affect imaging, ... though you may have already eliminated that as a source of error.

And as to software, the relevant download page has a surprisingly large number of driver downloads, suggesting that there may easily be driver-related issues, or functionality that doesn't like imaging activities.

I'm afraid I can't make good sense of your second paragraph: but until you have established that the dock is just a passive cabinet, you have to suspect that there's some software between the host and the actual disk, and take that into account.  (The 'capacity gauge' on the dock suggests it talks to the drive on its own ... ???)

You just might want to let the SeaTools test software check things out.

(Added: if you suspect that the dock enables some kind of HDD security functionality, without which you can't access it, you may want to check that out.  I have heard about special HDDs with non-standard interface pinout that need special adapters to work -- that's why I asked about  exactly which HDD you have.  The HDD spec sheet may help if you have one of those.)

If you have problems accessing files on the disk, then you can restore them using special software. For example, Rekuva or Uneraser. This is a simple solution.