Ever been able to solve this issue? I have exactly the same. Can't copy from my VM to UNRAID without explorer crashing. Although it depends.
I can copy just fine from my local Admin account (Password UNRAID = Password Windows). But I can't copy from my personal "online" account (Same PC, Same VM, just different log in), which has been setup with a PIN access.
My PIN is something like "e7f56Ukh" which would correspond to the users password in UNRAID as the online account password is >16char random.
Haven't solved it yet, but i think it has to be somewhere in this direction...
edit* It even crashes Qdir portable