Microwave beeps and displays E1, will not start a cooking cycle.

Safety first: Unplug the Commercial Chef microwave from the wall outlet before any disassembly. High voltage is present inside even when unplugged; do not touch the high-voltage capacitor or magnetron area unless you are trained.

Step-by-step checks:

• Inspect the door closure: Open and close the door firmly several times. Make sure the door is not sagging and that the latch hooks fully engage the cabinet. If the door feels loose or misaligned, the switches may not actuate correctly.
• Check for obstructions: Look for food debris or warped plastic around the door latch openings on the cabinet that could prevent the latch hooks from fully inserting.
• Access the door switches (for experienced DIYers only): Remove the outer cabinet screws and carefully lift off the cover. Locate the door latch assembly on the front side. You will see 2–3 microswitches (primary, secondary, and monitor).
• Test the switches: With a multimeter set to continuity, disconnect one switch at a time and test according to the markings (COM, NO, NC). When the door is closed, the primary and secondary switches should show continuity between COM and NO; the monitor switch should change state appropriately. Replace any switch that does not change state reliably.
• Check wiring: Inspect the small harness that connects the switches to the control board. Look for loose spade terminals, burned connectors, or broken wires. Reseat any loose connectors.
• Reassemble and test: Reinstall the cabinet, plug the unit back in, and test with a short 30-second heat cycle using a microwave-safe cup of water.

When to stop: If the E1 code persists after switch replacement and wiring checks, the control board may be misreading the door circuit. At that point, contact a qualified appliance technician.