Miele System lockwhat it means
Miele publish two separate locks with different behaviour. The system lock survives a power cut, which is why unplugging the appliance changes nothing.
Before you start
What this means
Miele are unusual in having two locks rather than one, and the difference between them is the difference between an appliance that seems dead and one that seems merely awkward. The system lock "prevents the appliance being used unintentionally" and is the stronger of the two: with it active the appliance will not run, and Miele state that it survives a power outage. The sensor lock is narrower: Miele say it "prevents the microwave oven being switched off or a cooking programme being altered by accident" by making the sensor controls unresponsive "for a few seconds after a programme has been started". Both release the same way — OK touched for at least six seconds — but the sensor lock only comes off "for a short period", and the system lock only until the appliance is switched off. Neither is set by holding a button: the system lock is switched on in the menu, Settings, Safety, System lock, On, and then takes effect when the appliance is switched off.
Miele put the release in front of you rather than making you guess: switch the appliance on and the display says System lock, confirm with OK, and the appliance then prints the instruction "Press OK for 6 seconds" and counts the time down. The one that survives a power cut is the important half of that.
On every other appliance in a kitchen, the universal owner remedy — turn it off, wait, turn it on — clears a surprising proportion of problems. On a Miele microwave with the system lock set it clears nothing, because the lock is a stored setting rather than a state, and Miele say so. The sequence that follows is predictable: the microwave will not work, the owner unplugs it, nothing changes, and they conclude the appliance has failed. It is worth adding that Miele put the system lock second in their own checklist for a programme that will not start, immediately after checking the door is closed and before checking whether the appliance is even plugged in. They know what this looks like.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| System lock switched on and forgotten | It is a stored setting rather than a transient state, so it stays set indefinitely and survives losing power. | Common |
| Released temporarily and re-armed on switch-off | The six-second OK only unlocks the appliance until it is switched off; Miele say the lock is reactivated then. Removing it for good is a menu setting. | Common |
| Sensor lock rather than system lock | Miele document two locks with different scopes and the same six-second OK release, and the display distinguishes them where the symptom does not. | Occasional |
| Set deliberately for small children | A reasonable use of the feature, forgotten later by whoever set it or never mentioned to anyone else. | Occasional |
What to try yourself
Switch the appliance on with the On/Off button and read the display. Miele put the words System lock there, so it identifies itself.
Confirm with OK. The appliance then displays the instruction itself — Press OK for 6 seconds — which is Miele telling you the release rather than leaving you to find it.
Hold OK for at least six seconds. Miele say the time is shown counting down in the display, so watch that rather than counting, and keep holding until the message goes.
Press a power level to confirm the appliance responds again. Miele say everything can now be selected freely until the appliance is switched off, at which point the lock comes back on.
To remove it for good, release it as above, then go to Settings, Safety, System lock and choose Off, and switch the appliance off. That is Miele’s permanent deactivation, and the same route with On is the only way the lock gets set in the first place.
If the controls go dead for a few seconds just after you start a programme, that is the sensor lock, not this one. Miele’s release is the same OK held for at least six seconds; it only comes off for a short period, and it is switched off permanently under Settings, Safety, Sensor lock.
Do not bother unplugging it. Miele state that the system lock survives a power outage, so a power cycle is the one thing guaranteed not to help.
Get a qualified appliance engineer to look at your Miele microwave
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What it costs to fix
Typical repair cost
£0
Time on site
3 minutes
Nothing. One button held for six seconds, and the appliance prints the instruction on its own display once you press OK.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Miele fault codes
- Demo modeUsually simple to fixThe showroom setting. Miele say the appliance does not heat up in demo mode, and Off in the Showroom programme setting, confirmed with OK held for four seconds, turns it off.Related: settings and modes
- Food in oven?Usually simple to fixA deliberate guard, not a fault. Miele will not start a programme it believes has no food in it, and they publish the exact trigger.Related: same brand
- Switches itself off during a programmeGet it checkedMiele publish a two-branch diagnosis for this. Clearing after a cooling period means airflow; doing it again after cooling means service.Related: same brand
- Close the doorUsually simple to fixA programme has been interrupted because the door opened. Miele publish it as normal operation, and the countdown resumes rather than restarting.Related: same brand
- Keeping warmUsually simple to fixNot the appliance restarting on its own. Miele publish this as an automatic function with figures: 80 W for up to fifteen minutes after a 450 W programme.Related: same brand
Own a Miele microwave? Save it and its codes come first next time.
Related guides
Common questions
I unplugged it for an hour and nothing changed.
Expected, and Miele document it. The system lock is stored rather than held in volatile memory, so it survives a power outage by design. That is precisely why so many people decide the appliance is broken.
What is the difference between the two locks?
The system lock stops the appliance being used at all and persists through a power cut. The sensor lock, in Miele’s words, prevents the oven "being switched off or a cooking programme being altered by accident" by blanking the controls for a few seconds after a programme starts. Both release with OK held for at least six seconds. The display tells you which one is set.
Nobody turned it on.
Somebody did. Miele’s system lock is switched on in the menu — Settings, Safety, System lock, On — and it does not arm from a held button or from cleaning the fascia; and once set it is only ever released temporarily, so the person who released it last time did not switch it off. It cannot set itself.
Is it worth using?
It is a genuinely good feature with small children in the kitchen, and Miele’s implementation is better documented than most. The only real cost is when nobody else in the house knows it exists.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.