Won't start game client after champ. select

I have the last 20 hours or so, tried to fix an issue where the launcher isn't able to launch the game client.

I yesterday I reinstalled my mac (with a format of hdd), installed macOS 10.12 and then League afterwards. the game client hasn't been able to launch sense then.

pre-condition:

1. Logging into launcher
2. picking any game mode
3. selecting champ.

Issue:

• After all countdowns has finished, I sometimes get the "Game still in progress.." and then the reconnect button appears, or just the reconnect button.

post: every time i press "reconnect" the game client don't event open, but I get stuck with the reconnect button.

Hope you can help me, Thanks!