Closed Fatal Exeption caught (UniverseServerExeption) Could not acquire lock for the universe directory

Happens. Every. Time. I don't know how to solve this incredibly annoying issue, which does not allow me to host when me & my friends play.

 

This should not be an issue with vanilla gameplay. If you have any mods installed which affect what planets generate or the density of the generated universe, pleasw clarify.

 

This happens when a Starbound.exe process is running a singleplayer game and you try to play single player in another process. You cannot play starbound's single player on two clients at once. Sometimes people find that the game is still running after it appears to close, you can open task manager/activity manager and close it manually and this will fix that.