Game will not launch (says the app is already running)

[Former user]

Hi,

Despite multiple Steam restarts, this game won't launch.. Every time it says that the app is already running, despite it being the first time I've tried to launch it since a force restart of Steam.

I'm fairly new to Steam... am I doing something wrong?

[victor sosa]

is this a MACOS???

[dalerank]

Duplicate of #458.