I'm running Windows 10 pro 64bit and after playing the past 2 days fine it won't open today so I'm using the file checker right now

i mean all and all pso has been broken like this for years but only on specific builds of windows older versions of windows work better cause the support they have for windows 10 is pretty bad. This is why a lot of games dropped using nprotect cause it prevents a lot of systems from working properly. Its great to stop hacking but if your punishing people from playing the game its counter productive. And honestly there hasn't been a fix for a lot of people who experienced the problems. Which is likely why you wont see an admin post trying to help.

nprotect is a rootkit so if your using anitvirus it could be removing it from the folder

@HoDKenji To delete the folder for pso inside of the windowsapp you have to give yourself access to it by going to properties and advanced and then adding your account name to it in order to delete it. It seems like all the old problems are still a thing. It also seems if you try to install it on a drive that isnt C it wont work.