This message appears when you try to delete Virtual Machine from Hyper-V Manager:
The operation cannot be performed while the object is in its current state.
If you go manually to delete the folder where is VM located you will get an error message that you don't have permissions to do that. Into this folder there is config XML file:
Solution for this issue is to find the same XML file in :
and to delete it.
Note: First you should enable: Show hidden files, folders and drives in Folder Option.
After that when you open Hyper-V Manager you will see that the machine is gone.