See this comm center thread started by Stephane Basa. The MPCORB and MPCCOMET folders under ASCOM can get locked for users. Then the tool fails. Add those paths to the security fixups in the Repair Security tool inside ACP.
Attached the make files from this post by Dick.
I have attached the latest UpdateMPC.js from Dick and will add it to the master branch. Also look at this info from Dick on the status of peoples' permission issues with this.
Another thread on this. Want to get the "final" for the next release. Wait on Dick now.
PowerShell issue on Windows 7 still not solved.
Another issue cropped up as described and fixed by Dick and Eric Dose in this thread. Roll all of this in for the next release.
Dick has kindly rolled up the issues involved in this post on the Comm Center.
This is also being discussed in the original auto-update thread by Dick Berg.