I may be late to the party here. But I have had very few issues since PSO2 Came to PC. Also, I was able to install the Newest Windows
Update and thankfully, things are still smooth as silk so far. As far as this issue, I have seen numerous instances where players have had their game erased. Maybe I can share some things that hopefully, can help you as well. ( If you don't find resolution to your ailment, please by all means send in a support ticket query.)
You may already know this, But once you have completed in installing PSO from the MS Store app, You SHOULD NOT use the MS store app to launch the game. I'm getting feedback from many players that this behavior inevitably triggers a "RE-INSTALL " and proceeds to erase your game files. IF you have updated everything and all files remain, just make a shortcut on your desk-top that you can click to launch PSO2.
|INCOMPATIBLE SOFTWARE FOR PSO2
You may also want to check out the ever so-growing list of incompatible software that causes for many players issues with PSO2.
|PSO2 WAS INSTALLED IN AN INCOMPATIBLE LOCATION
This is something that is being repeated over and over, Many players trying different thing so that PSO2 will work once more.
My advice? Well, just install PSO2 in you C drive. Please, DO NOT install it anywhere else, DESKTOP, DOWNLOAD FOLDER,
DOCUMENTS FOLDER. Why? Well upon doing so, windows then sets EXCLUSIVE file permissions to that install location and it's the reason why "It may work for a while , Then suddenly ... " My files are gone."
Hopefully this will aide you and make your update transition as smooth as can be!