What should I do if my microwave stops working?

Updated : 6th October, 2026
A Samsung microwave in a kitchen

If your Samsung microwave has stopped heating or appears to be running without warming food, the cause is often a simple setting or installation issue.

Demo mode, an accidentally activated Kitchen Timer or a door that isn’t closing properly can all prevent heating.

Checking these settings and ensuring proper clearance can usually restore your microwave’s normal operation.

Please note: Sensor Cooking and Auto Cooking results may vary. As long as the food is getting warm, the microwave does not need service. In some cases, if you are cooking a very small amount of food, you can improve cooking performance by increasing the quantity.

If your Microwave has stopped working, try checking the socket. You can plug your microwave in a different plug, or try the plug with another small appliance.

When a microwave is in Demo mode, you can use all the functions of the microwave, but it won't heat anything. This is because the magnetron is not turned on.

An easy way to test for Demo mode is to set a cooking time and start the microwave. In Demo mode, the timer counts down much faster than usual.

If your unit is in Demo mode, turn it off. For models with an Options or My Settings button, Demo mode is option 6 in the menu - setting it to 2 will turn it off. For any other model, refer to your user manual for instructions on how to exit.

Make sure that the Kitchen Timer option was not accidentally used instead of a normal cooking cycle.

Make sure the door closes completely. If the door is not completely shut, the microwave may run but will not heat.

Use a damp cloth to wipe the door and frame of the microwave; debris could be preventing it from closing properly.

Please note:

  • Over-the-range models have different clearance requirements and should be installed according to the installation manual to ensure they vent correctly.
  • If the microwave has not been working since it was installed, check the installation of the vent.

If the microwave does not have enough clearance on each side, it will be unable to vent properly. It will either not heat or have weak heat.

Check the clearance to the left, right, above and behind the microwave. The space requirements vary from model to model and are included in the user manual.

If you have tried all the solutions above and your microwave still isn’t working, please contact Samsung Support.

Thank you for your feedback!