I see the thread from last year but never read a solution The HTPC in my Master Bedroom just experienced the same issue. I thought in maybe a corruption of some sort as I was also unable to get to any of windows admin tools.
I restaged the machine today from a newly formatted HD with W10 Pro 1909. Sure enough, when setting up the MC24, restoring the license and setting up the tuner, no channels are found. The setup program sees the 4 tuners and all boxes are checked. When entering the scan function, I notice no tuners are listed in the popup window as it used to.
It seems to be related to the 1909 load and Net framework. Everything was working fine before this load. Are any corrections available?
The HTPC in the living room is running MC25 and there no issues except I had to change over to schedules direct or perc data. Looks like Rovi has had issues for a few days.