Put the summary of the bug you're having here
What I expected to happen was...:
The game should start
What actually happened was...:
It opened game output and wrote:
Completely ignored arguments: [--nativeLauncherVersion, 1206]
[21:30:36] [Client thread/INFO]: Setting user: N0elPL
[21:30:39] [Client thread/INFO]: LWJGL Version: 2.9.4
Steps to Reproduce:
1. Start the game
2. Done it shows game output
Try MC-112780.