The steps listed in this thread did not work for me and I cannot understand how or why it has worked for others using Windows 10 or later. I am positive Microsoft corrected this "workaround" a long time ago due to obvious security concerns.
The only viable option for me was doing system restore using file history. Did you have file history or system image/backup scheduled and running or did you make a recovery drive? If so, you should be able to use one of those options.
I tried using my system image but it would not work. I was able to use file history to get back in but then had to clean up the mess from renaming and moving files as suggested... I would not go messing around with utilman.exe if I had to do it over again.
I now have file history running every 3 hours along with weekly system back with system image. Additionally, I purchased a small USB thumb drive and made a recovery drive, which I recreate/update monthly.
Good luck.