5.3 just happened 2 days ago. I open my launcher now, and it says "Calculating differences: 1 file scanned, 33%" Everything in the launcher has the wrong resolution and it doesn't show Archlight Vel'koz picture or Champion Rotation picture. I'm not sure how to take a screenshot of this but I hope this can help get it fixed. Server :NA 
My launcher is having the same problem. It will start up and then freeze and won't show the launch button. Then it gives me the bug splat. I've tried everything within my power to fix it but it's still not working. Please help! :(
I have this problem too; i play on EUW, my launcher opens and keeps "calculating" differences. over 15000 files scanned in a couple of hours before i decided that this wasn't going to work. i Do get the immages, and i sometimes can hit the hitbox of the "launch" button, giving a proper sound, but doing nothing else.
Same here, keeps counting files but is stuck at 33 %. What can I do to fix it?
Finally worked (2 hours later) .-.
