League new client unable to lock in after changing masteries

My new client on macbook pro Sierra system does not respond correctly at all. I was playing in Ranked and after I changed my masteries on the new client system popped up an error message. Then the lock button and the masteries page faded to dark and I was unable to get a response from clicking. I wish riot fix this new client, like for real I have been forced to dodge games for so many times.