Just wanted to share this as I sat through 3 installs after attempting to repair corrupted the whole game. Just type "store" n the search bar and open the game from the "PLAY" button off the MS store. This is a workaround for those of you finding that the game won't start up after you've played it once and restarted your PC.
edit: Eventually it once again stopped working and tried to re download itself again. I've deleted everything now and will wait for a proper install option. I will add that if you are going into the windowsapp folder to find the mutablebackup folder and delete it, make sure you don't change ownership of all subfolders in the windowsapp folder as I did. It wont cause problems immediately but can lead to security vulnerabilities in the future. You only need to change ownership of the windowsapp folder so you can get inside, then change ownership of the mutablebackup folder and all of its sub contents. This will allow you to delete the multiple installs of the game and free up HDD space. You might need to restart to finish deleting them if you tried to run the game because gameguard for pso2 is in there also and can not be deleted if it has been run since your last restart.
Very sad to report all of this. I had fun for 3 or 4 hours. Hopefully they can get it working but I fear the Microsoft store will bring this one down in the end. What a terrible decision made by SEGA.