My PC was originally Windows 7 just when 10 came out, then I added RAM, an SSD and then free Windows 10 upgrades from 0001 thru 1903. I have always been an Administrator.
Apparently the update from 1809 to 1903 disabled security permissions inheritance for random top-level folders, including but not limited to c:\users\.
It also messed with "ownership".
I took "ownership" of, and enabled inheritance within, key folders on all of my logical drives.
UAC, and hence Auto-add, works perfectly now.
Enabling inheritance is easy once you figure out it is broken. In Explorer, right-click a folder, then click properties, security, advanced, then click the inheritance button in the lower left corner.
Taking ownership is easy if you run the following in an elevated command box:
Code:
To take ownership and grant full permission on a folder:
takeown /f foldername /r /d y
and then:
icacls foldername /grant administrators:F /t
DaltonST