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 ?????
I started to think the same but now my patcher says "Applying patches" and it's not stuck anymore ! 
same 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..)
