@Jasepo You need to go to the folder the game is saved in , then right click microsoftflightsim.exe and give it administrative permission (look online if you don't know how to do this), then restart computer, and try again, it worked for me im 60% through the install now, probably have another 12 hours or so to go... you can find a guide online to give you more in depth instructions.

run "what" as admin? I'm launching from Steam......

run as admin and it will work

The exact same happened to me. I restarted my computer and got past the screen - the downloader has just crashed for the second time however...

I have had the self Problem, i restart it 4-5 times and then it has jump in the normal download screen.Now the Download Works fine .Best Regards

even if you refund now, the next time you purchase it. The installation time of 90GB will still be counted into your game time.
I suspect they did it so we cant refund. Lol just kidding.
But to be real, the launcher downloads super slow.

For me download is complete (500MB + around 91GB), restarted the game and system several times, on launch it is always stuck on this screen

Restarting the game has no effect. Until this is resolved I submitted a refund. I won't allow this to be run and count the play time until ineligible for refund

You need to restart the game. The actual download screen is after this screen.

I'm pretty sure this is showing download progress, I'm also at this point.... with the bar stuck at exactly the same point. I'm guessing the MS servers are overwhelmed.