I had the same problem twice the first time i downloaded the game again and the second time was triggered the same way the first by saying "no" to the launcher... it forbidded almost 5,000 files... this time I downloaded the Tweaker and before you install it make sure you have the Developer Mode active and to access it, head to Settings > Update & Security > For Developers and select “Developer mode”. after that installs, install the tweaker and in the options menu in the tweaker menu select "Tweaker Settings" and then "Select PSO2 Folder" and select the folder location at "C:\Program Files\ModifiableWindowsApps\pso2_bin" or where you decided to install it, then save and select "Troubleshooting" and in the upper left says file check and select the new method option then wait until it check the files and downloads the info that it was missing... and when done hit "Start PSO 2" or run the launcher and be sure to hit yes even if you clicked by error and then play or close after the launcher executes... (this is how it worked for me, I hope it works for you all)

PSO 2 Tweaker: http://arks-layer.com/ (select the Tweaker Setup) PSO 2 Tweaker Install guide: https://na.arks-layer.com/tweaker-install.html & https://na.arks-layer.com/tweaker-setup-b.html