Left for Dead 2 only one instance

Aug 19, 2015 at 12:16 AM
Edited Aug 19, 2015 at 12:59 AM
Every time I try to run Left for Dead 2 it gives an error that only one instance of the game can run at a time. I have been able to play Borderlands 2 and the pre sequel but this keeps erroring, it seems like the StartGame.exe is not stopping the valve hooks to prevent it noticing how many instances are running. Any ideas what I can do to fix this?

Edit: After further work I have been able to determine that it is hl2_singleton_mutex that is not being killed, if that handle is killed it works, but it I kill it by hand I cannot get the controls to tie to the right instance after. Help?