[NEED HELP] cant start the game/ session lock problem

when i try to start the xonotic.exe i get the fallowing error: btw the game is installed in the documents directory
session lock c:\users\/xonotic/lock could not be acquired. Please run with -sessionid and an unique session name.

Before you start the game, in your game directory, try to delete the files with names beginning with "lock". And then start the game.