"The game is already runnning in this directory"

Not being able to start to play, it says "The game is already running in this directory" and refuses to start. Pressing Start anyway doesn´t help. 
Restarting the PC (win 10) doesn´t help.
Changing the password doesn´t help. 
Closing the app or processes doesn´t help.

Updated windows and Java, no luck.

Getting really frustrated. What should I try next?