Cant open client?

Ever since the new client update I couldnt even open the league client sometimes. There are sometimes where it opens and everything runs smooth besides the laggy client but there are more times where I try to open league but it won't open anything. I tried reinstalling league and it worked for like 2 days and now I cant open league anymore. I play on Mac Im not sure if its a Mac only problem but I just wanna play league :(