So I went past the 1813 error, uninstalled the game 3 times now, tried alot with take ownership and the mutable folder / backupfolder I tried some powershell codes but nothing works. Doesnt matter what I do, when I click on "play" on the microsoft store or start the game in the folder that error opens "cancelled startup of pso2updater.exe" and then closes. But when I try to start the "pso2startup.exe" manually in the folder, nothing happens. Nothing starts.

At this point im just waiting for them to fix the damn microsoft store and hoping they gonna launch on steam on the next days, otherwise this game is gonna be dead for so many players.

I agree that it should have just launched on steam. Like yourself, and so many others, I wasted so much bandwidth, formatted my drive numerous times, changed my network settings etc and still nothing. I wish they had done a better job at testing things out.

i have a magic solution! go to apps & features, search phantasy star online, select advance options and there, reset and repair the app. I couldnt update the up before, and after that the game update properly, i hope it works for someone.