Group Policy Editor Error

My Windows 10 PC just updated itself to 1703.
I have a script which used to run perfectly on Shutdown, but now it does not - I just get an empty black box and nothing happens. (The script still runs fine if executed manually)
When I open the Group Policy Editor to investigate I receive the following error message:

I click OK, the message box closes but then reappears.
I click OK again and the message box closes (It reappears only when Group Policy Editor is opened again on another occasion)
The editor then appears to be working.
So there are two problems which may or may not be related.
Any help appreciated.

Many thanks for your assistance.
By following the link you provided I have successfully eliminated the Group Policy Editor error message.

However the first problem remains - my script does not run correctly at Shutdown.
This is all that I have done:


This used to work fine before the 1703 update, but now when I shutdown, I simply see a tiny window (C:\Windows\system32\cmd.exe) with nothing apparent happening. The window can be enlarged, but it contains nothing.
I thought maybe the script was running and I could just not read what was happening (black text on black background I thought!) but when I try to edit the font and colours in the cmd window by going to the cmd window properties dialogue, I find the dialogue box is blank so I cannot proceed.
I am rather baffled.
I should add that none of the above happens when opening a command window at any other time than Shutdown. Everything is quite normal then.