Microwave will not start; display shows E1 immediately or when pressing START.

Safety first: Unplug the microwave from the wall outlet. Microwaves contain high-voltage components that can retain charge even when unplugged. Do not touch internal high-voltage parts (capacitor, magnetron, transformer). If you are not experienced, contact a qualified technician.

Step-by-step checks:

• 1. Inspect the door and latch: Open and close the door several times. Ensure the door closes evenly and the latch hooks fully engage. Look for cracked or bent latch hooks on the door and damaged latch receptacles on the cabinet.
• 2. Check for loose door: If the door sags or feels loose, the hinges or latch may be misaligned. Gently lift the door while closing; if the error disappears temporarily, alignment is suspect.
• 3. Access the door switches (for experienced DIYers only): Remove the outer cabinet screws and carefully lift off the cover. Locate the door switch bracket near the latch area. You will typically see 2–3 microswitches (primary, secondary, and monitor switch).
• 4. Test switches with a multimeter: Label wires, then disconnect them from each switch. Set the meter to continuity or ohms. With the door closed, the primary and secondary switches should show continuity; with the door open, they should be open. Replace any switch that does not change state correctly.
• 5. Inspect wiring harness: Check for burnt, loose, or broken wires at the switch terminals and along the harness. Reseat any loose connectors.
• 6. Reassemble and test: Reinstall the cabinet, plug the unit back in, and test operation. If E1 persists, the control board may be misreading the interlock circuit and should be checked by a technician.