Spectating a Friend Bug

I wanted to spectate my friend, but instead of the loading screen i was met with an error, saying that the game crashed. I thought that was fine, but that error repeated over and over again, not letting me out of the tab, even alt+f4 didn't work, so i decided to restart my computer. When i turned it on and got into the client this https://paste.pics/b8c7f94e9cb2f73c6d4bf542ce4b3f13 happened. I can't play the game, or access the shop, or hextech crafting, making me unable to play the game. What do i do?

The fix is probably deleting some file but i just don't get how a bug like this can go live.