[CRASH HELP] please help i miss playing!!!

So the new mastery's came, i selected new ones for most my champions already. and then the next 2 days I logged in and there's a pop up saying 'new mastery's have been added would you like to update them now bla bla ... yes or no' and now my client always crashes as soon as this message appears. I can login fine and launch fine. I tried reinstalling and i also tried repairing....

Help please?

thanks!