World of EUC

Have a Look to the diskmgnt and assign a driveletter. 

I am the owner already.. "you dont have permission to mount this file"

Have a Look to diskmngt. I think the disk is still mounted without a Drive letter

I can see it in Dsk Mgr and assign it a letter, but double clicking on the drive does nothing

Even in file explorer, E:\ it will not open?

Never seen this before. Can you try this on a different vm

There must be something wrong with the permissions.  I use frxcontext.exe, give it a try. 
<https://learn.microsoft.com/en-us/fslogix/disk-management-utility-reference|https://learn.microsoft.com/en-us/fslogix/disk-management-utility-reference>