Okay so I finally figured it out, I looked online, near and far and i finally fixed it.

So I was like you, my PSO2 Client wouldnt load, so i went to the MS Store and the download bar was not showing any progress and when i tried to Repair/Re-Install and still nothing. Tried removing it and did the whole giving me access to that file (trust administrator or w.e it was called) Just do what I did.

  1. Control Panel > All Control Panel Items > Recovery
  2. Open System Restore (NOT RESET PC)
  3. If you don't have a save point just make one manually(I did mine today) (or if its auto to the earliest date)
  4. Let your computer do its thing.
  5. Go back to MS Store and the game should say you OWN it, and just hit download and the BOOM (or i am hoping it works for you as it worked for me)

I hope this helps anyone that is having this annoying problem, I have not ran into any error code or launching code problems sorry.

Best of Luck - KittyMilk