I am up to date (5.14) but the patcher is scanning over 5000 files and counting.. Occasionally it will due this for just a second but now its scanning everything for no reason 
Any reason for this ?????
AlxndrPistoletov1 votesI started to think the same but now my patcher says "Applying patches" and it's not stuck anymore ! 
3ofGot40ve1 votesYah happened to me too.. Just took forever! It works now though 
Fish401 votessame story over here, i tried several things to fix it but none of them worked...
maby this will work for you:
HOW TO FORCE A REPATCH:
Go to your Riot Games folder (Default path: C:/Riot Games/League of Legends) Open the following directory: C:\Riot Games\League of Legends\RADS\projects\lol_air_client\releases{highest version number} Delete the following files: releasemanifest S_OK Open the Deploy folder Delete the following folders/files: lib (folder) META-INF (folder) mod (folder) lolclient.exe (file) lolclient.swf (file) locale.properties (file) Restart League of Legends
(sorry for poor english..)