If you're unable to locate the Scarlett playback engine in ProTools, consider these steps: - Ensure the Scarlett is powered on by flipping its switch to the down position. If ProTools is running, restart the application to apply changes. Instead of this potentially time-consuming step, you might first check System Preferences > Sound to verify if the device is recognized by your computer in the first place. If the issue persists, try disconnecting and reconnecting the USB cable from both the Scarlett and the computer.