Microwave does not start at all; display is lit and buttons respond, but pressing Start does nothing.

Safety: Unplug the microwave before cleaning or moving it.

• Check child lock: Many Bosch microwaves have a control lock. Look for a key symbol on the display. To unlock, press and hold the designated key (often the Stop/Cancel or a specific combination) for 3–5 seconds as described in the user manual.
• Test other buttons: Try setting the clock or changing power levels. If only the Start key fails to respond, the touch panel may be defective.
• Verify door closure: Open and close the door firmly. If the display shows a door symbol or does not allow time entry when the door is closed, the door switches may not be engaging.
• Power reset: Unplug for 5 minutes, then reconnect and test again.

If the unit still will not start: The Start key circuit, door interlock switches, or control board relay may be faulty. These require internal access and should be serviced by a Bosch technician.