Due to Microsoft repeatedly dropping the ball with their updates lately, I’ve been wary of immediately updating.
It’s been better to wait for a few weeks to months until the bugs are sorted out. So, as I have the option with Pro, I had my updates paused.
So I’m still on version 1909 and plan on staying that way for awhile. But even If wanted to update, Microsoft is blocking 2004 update from happening . Welcome to crowd-sourced QA.
But anyway, I restarted the updates, which were paused and it installed Quality Update KB4549951
After restart…Scaler 2 works!
Dunno if installing KB4549951 is what fixed it. Maybe having updates paused in Windows Update prevents some other change to system configuration happening. Reminder that maybe because of this setting, I didn’t get any runtime installation on my desktop after I first installed Scaler 2, but did on my laptop. There it prompted a restart and Scaler 2 worked from the get go. Also, as the laptop is version 1903, there’s no KB4549951 to install, so due to that I don’t think KB4549951 is the "fix itself but having Windows Updates not paused.
So to conclude, if you have updates paused on your Windows 10 Pro, unpause them and let Windows update, restart and see if Scaler 2 starts working. @luapmartin
PS. PEBCAK! 