Sometimes it's not an option for people to clean install... for me, I have so much audio software and so many plugins it would take me months to start over. I do however create a Veeam backup of my entire system before attempting a windows update.
I posted above that there is an offical MacAfee removal tool but even after running that, the upgrade didn't work. But it's worth running anyway just to get rid of the remnants.
It would be good to hear if anyone else can get the update to work by checking secure boot is on in bios... I had switched mine off a few years ago to allow me to run other non-standard OS's and not switched it back on.
On another thread, someone elses secure boot was off but greyed out so they couldn't switch it on. They updated the bios (I assume this then switched secure boot on) and then the update worked for them.
It's worth a try and something no one else has seemingly looked at yet