The one thing that has worked for me, tested it quite a bit is this:
http://www.reddit.com/r/leagueoflegends/comments/1gn3vt/fix_crash_after_champion_select/
I just figured this out. If you are having problems with your League crashing immediately after champion select and you have logitech software I HAVE THE FIX FOR YOU, also if you are experiencing this problem and don't have any Logitech products, it wouldn't hurt to try it too!
Edit4: Logitech hardware support can now be disabled by adding “LogitechSupport=0” to the “General” section in your game.cfg If you use any Logitech peripherals and have drivers installed they can cause League of Legends to crash rather frequently so you’ll want to apply this fix that Riot didn’t explain very clearly. The file game.cfg is located within the Config folder found in the League of Legends directory, the full default path is C:\Riot Games\League of Legends\Config\game.cfg. To edit it, open it in a plain text editor like Notepad. The file is split into sections, look for the line [General] and paste "LogitechSupport=0" (without the quotes) directly below it and save, all done.
Go to: C:\Riot Games\League of Legends\RADS\solutions\lol_game_client_sln\releases\x.x.x.xxx (folder with LARGEST number IE 0.0.0.238)\deploy
In this folder, delete or RENAME two files, LogitechGKey.dll and LogitechLed.dll. This should hopefully cause your client to not crash anymore. I would recommend just renaming these files, or if you are going do delete them MAKE SURE you make a copy of them first, in case you need to restore them in the future.
I have been suffering from this problem for MONTHS.. in fact.. ever since they released the logitech update.. from debugging league, I discovered that these files are causing a memory violation, whether it is due to Logitech Gaming Software, or just poor programming in general.. not sure...
I hope this helped.
PS: I do not have a Logitech keyboard, rather I have a G930 headset. So if you're wondering whether or not this only pertains to users with keyboards, it does not. It pertains to anyone using Logitech hardware.
EDIT: To further clarify, if you are running Logitech gaming software, do my fix. If you experience crashing after champion select but are not running LGS, try my fix but don't delete the dlls.. Just rename them. If it didn't help you, just change their names back. That will ensure that nothing will be broken for you.
EDIT2: To be SUPER-DOOPER clear: The problem that my solution pertains to is: The game crashes right when the loading screen is supposed to show up, after champion select, but then the client would just disappear; and when you go to the riot icon in the system tray the pvp.net client would be open but there was no reconnect button or it is greyed out.
EDIT3: You all made my morning! This is my first time even getting remotely close to the top page, and I got here by helping people, rather than posting something like "HotShotGG did a funny dance with Teemo" and getting silly upvotes. I feel like my upvotes are representations of gratitude, and that makes me feel great! This morning I got up for work to see all the Reddit love and I couldn't help but feel a great sense of satisfaction that I helped so many if you out. God knows I was getting no where with Riot tech support so I know your frustrations!
EDIT4: Thank you for the love, Riot rewarded me for my troubles with a bunch of free RP.. which is awesome! I also got Reddit gold from a viewer as well! Thank you so much! Glad I could help!
