Bump, I have this same issue - never installed any anti-virus software nor had any prior issues. I've kept my system up-to-date, ran SFC and did all troubleshooting steps in this thread to no avail.
If I get told to restart my computer one more time, I will lose my sanity.
"This setting is managed by your administrator", but I am the administrator...
Thanks
It seems this is going to be a never ending story. MS does not respond so until when do we have to wait until a proper answer will be given?
Thanks