After testing, I have found that the game crashes if one is playing on Windows 10 Technical Preview. I've tried a custom game with 
and with 
and the same crash occurs, however in custom games, the SR map becomes dyed in a sepia tone.
I'm having the same problem, however I'm on a Mac. I don't know if it's the patch or my Mac. I don't really think it's my Mac though, because I was playing during the 5.4 it was working perfectly.
I can confirm this is happening with me as well.
Windows 10 Technical Preview, after patching to 5.5 the game crashes 3 seconds after joining the game. Can't reconnect to my game, and now i'll likely be labeled a leaver. 
I cant even start the game without it crashing my entire computer. I'm on Windows 8.
Having a similar problem. I patched and didn't restart my PC so I thought that was the problem because when I ALT+esc out of the program then go back in the game would glitch in and out of windowed mode and I couldn't use any abilities, only pings. So I restarted and I tested ALT+esc again and the same bug appeared. Also getting a higher ping and lower frames than usual :/ So much for not ruining toasters huh Riot?
if i login my screen frozen i cant move my mouse and nothing help pls fix
Same issue here! Both my friend and I use windows 10 tech preview, and 5.5 broke the client. You connect, after 3 seconds it crashes everytime. Please fix this riot! We can't play the game.
I'm having the same issue after 5.5 it crashes.. and very laggy in game.. Riot please do something!!
Can you guys help me understand something? As beta testers, why do you expect live software to be updated for a beta operating system? Riot could spend thousands of development dollars trying to make it work in Windows 10 only for Microsoft to patch it and make it not work again? Live Applications are built for released operating systems, not beta. When you agreed to be a beta tester for Microsoft in the agreement it says it's not recommended to install and expect viability of end user applications. Sorry it's broken for you, but as a beta tester that's literally what you signed up for - to find issues and report them. My 10 received an update yesterday, don't know about yours and now most of my DirectX applications aren't working - I would image that's the root cause, and as a beta tester I reported to Microsoft, not Riot.
Exact same issue here. Also in Win 10 preview.
