I have Avast antivirus. When I started the game it moved pso2startup.exe and pso2.exe to virus chest. I restored those files and added an exception so that they wont be moved again. But, now if I start the game, the launcher works fine but after clicking on Start Game it just closes with no error and nothing starts. Tried running the Check File option in launcher couple of times, restart pc, but still wont work.

Here is the fix that worked for me:

  1. Add pso2startup.exe and pso2.exe to exception list of your antivirus. These files are usually present at: C:\Program Files\ModifiableWindowsApps\pso2_bin
  2. Delete pso2.exe from game folder. You will require administrator permissions for doing so. NOTE: Make sure to make a backup copy of pso2.exe
  3. Start the game the way you usually do.
  4. Now first launcher will download the deleted pso2.exe file. After that it will automatically run Check File, just like the first time you started the game. It wont download any other files if everything is proper.

Now the game should launch. I hope this helps.