PLEASE LIKE THIS UP TO HELP ALL THAT SEES THIS!!!!!!!!
a couple patches ago i had the same problem. went 6 days without being able to play because it wouldnt work. what i had to do was open the league file its self. go to the rads folder, go to the projects file, then the lol_patcher, then releases, next 0.0.0.21, then deploy, next scroll down and you will see two applacations 1 will be "lol patcher.eve" and the other one will be "lolpatcherUx.eve" MAKE SURE YOU OPEN THE FIRST ONE!!!!, now it will manualy patch your client. only problem is it will take around 3-4 hours to scan all of the files (around 20,000) your just going to have to sit threw it.
this is the only way i was able to fix it. and every time it needs patched i have to do this system. and it takes forever but its better than playing smite ;D