I have this same problem, if you are on windows, open the task manager, then look for a task called Minecraft Launcher, and then look for a possible identical task. Close the one using more memory, and your game will start.
I have this same problem, if you are on windows, open the task manager, then look for a task called Minecraft Launcher, and then look for a possible identical task. Close the one using more memory, and your game will start.