Todd et. al. -- Peter Simpson, lead ASCOM Platform developer, has identified a clear Microsoft botch where they have left a stray SID in the update, and caused security ordering errors that the registry editor and windows explorer security utilities pick up and fix. It's not the ASCOM platform it's the WIndows 10 updates. You might have noticed the funny message at the end of ACP's install that tells you to hang on to your ACP installer and use it to fix the corruptions left by (some?) Windows 10 updates.

There will probably be a new ASCOM Platform soon, and it will contain a workaround to the Microsoft screwups. MS definitely knows about the issue, so hopefully it will die down over the next year.

PS< This thread crept a long way... I don't know where to move it or not to move it. Look at the title ha ha. I might split it. What do you think?