Download and reinstall the latest version of OpenAL to restore the required audio drivers for the game. 2. Verify Game File Integrity (Steam Users)
TechnoBrain, the game's developer, notes that security software often blocks the game from creating necessary files in the Documents\TechnoBrain\ATC4_g folder. I Am An Air Traffic Controller 4 Application Not Found
Many players have found that ATC4 fails to launch with vague errors if (Open Audio Library) is missing from the system. If you recently performed a "clean up" of your PC, you might have accidentally removed it. Download and reinstall the latest version of OpenAL