OS Yosemite. Why does it stop at 87%?

Hey all, So, i updated to OS yosemite, and ever since then I have had connection issues and getting kicked from games. So much, that I even got a 5 game ban. I really didn't mean to leave all these games, but my client kept crashing. It had never done this till I updated to OS Yosemite. So what I did was i uninstalled league and tried downloading it again. I keep on getting the download to around 87% and then it just refuses to update. Any suggestions or tips or tricks? I have scoured google and couldn't find anything of use. Id really appreciate the feedback