I installed the SDK and had a quick browse of the menus available in it, making no changes other than loading the DA62 in-game.

After quitting and restarting FS2020, the program now hangs indefinitely at the 'checking for updates' screen. The only change I've made is installing the SDK and installing Aerosoft's freeware Paderborn airport.

Any ideas what I can do to get the game running again?

Uninstalling both Paderborn and the SDK, with reboots in between, didn't help. Looks like a full uninstall and reinstall is the only cure. The game gets as far as the 'welcome, set your experience' splash screen (the one after 'press any key to continue') and then hangs on 'checking for updates' The spinning wheel progress indicator freezes almost instantly. Program ticks over at about 1.1GB of memory and ~9% of CPU in this frozen state. Weirdly, the menu music keeps playing OK.

For anyone who reads this in future trying to troubleshoot a similar problem, this was a stock installation. No mods, the only addon prior to installing Paderborn and the SDK was Orbx London landmarks as published on release day through the FS2020 marketplace.

edit to add

IMPORTANT: IF YOU TRY USING THE WINDOWS 10 'RESET' OPTION IT HAS THE SAME EFFECT AS UNINSTALLING THE GAME. YOU WILL HAVE TO DOWNLOAD ALL 100GB AGAIN FROM SCRATCH.

Windows Settings > Apps and Features > Microsoft Flight Simulator > Advanced options > DO NOT CLICK THE REPAIR OR RESET OPTIONS UNLESS YOU WANT TO DOWNLOAD THE WHOLE GAME AGAIN FROM 0!

Edited August 30, 20205 yr by lambourne

I had problems with too (although I didn't download the SDK) and I eventually found that if I went back to the Microsoft purchase sight, found my ownership and clicked on the Install/Play button a couple of times the sim reloaded from there and everything was fine. 

/ply