Washer-dryer will not start a cycle; display is on but Start button does nothing.

Safety first: No internal power work should be done with the unit plugged in. Unplug before removing the console.

Steps to resolve:

• Check door and lock: Ensure the door is fully closed and you hear the lock engage when pressing Start. If not, inspect the door lock as described in door lock errors.
• Verify control lock: Make sure the control/child lock is not active. Disable it per the user manual.
• Try different cycles: Select another cycle and press Start to rule out a specific program issue.
• Inspect UI board: If the Start button feels unresponsive or stuck, remove the console and inspect the user interface control board. Replace if the Start switch is defective.

If the UI is good and the door lock works, the main control board may not be recognizing the Start command and may need replacement.