There is this rare bug where if I want to restart the game it doesn’t let me, because it’s already running. Except it isn’t. This might be Steam related as it is Steam giving me the error message and I can’t see the game running in Task Manager.
I can resolve it by closing steam, which then asks me if I want to close Infraspace first.
So far it happened twice. Once after I closed the game by clicking the red X in the upper right corner and once after I closed the game normally.