I’d first submit a diagnostic, so Sonos can help you figure out what’s going on, then I’d unplug it from power. 

I have the same problem, what to do ? It can’t be unplugged as it has its own power, of course.

Keep the power button pressed for up to 10 secs.  That will force the unit off.

Same. This keeps happening to me all the time. Power down works but eventually it comes back. 

If this keeps happening, maybe grab a mobile video recording (that might be helpful to your case) - then contact/chat to Sonos Support with a system diagnostic and see what they say. 

This happens frequently on my Roam speaker. A piercing, loud, siren-like wail that is so loud it actually hurts my eardrums. I called technical support and they have been no help. They say to run a diagnostic report when it occurs, but the sound is so loud (neighbors can hear it) that all I can do is hold down the power button for 10 seconds to kill the speaker. Any ideas?! I’m at wit’s end. 

Without that data, I’ve not got a clue what might be causing that issue. Might be worth trying a factory reset toforce it to reload the OS, and see if it continues, but if it does, it’s likely the diagnostic will be the only way to tell. 

I’ve not heard that noise mentioned here in the community before either, but as Bruce says if a reset doesn’t sort it, then maybe video it …and try to get a diagnostic report and then contact Sonos Support as mentioned in my earlier post above.

This noise actually happened to me during surgery I had to scrub out and put it outside. I threw it on the ground and still wouldn’t turn off. It finally turned off after like a minute. The surgeon was not too happy about it. Needless to say I returned this to Costco since I can not under no circumstances have this happen in my OR again during surgery.

This happened to me at 3am this morning and was probably one of the scariest/loudest noises I have ever heard. Had to hold the button for 10 seconds to stop the madness, but am now worried this will randomly occur again. Makes me want to throw the speaker out if that means not having to wake up to that again.

This just happened to me at 3.55am in the morning- woke up half my apartment block of neighbors, & scared the * out of me. Eventually got it turned off by holding down button for 10 seconds- clearly it's happened to other people, but nothing from Sonos as to why? 

*Moderator Note: Modified in accordance with the Community Code of Conduct.

Did you submit a diagnostic, and call Sonos? 

They don't open until 10am. The chat bot was no help

As long as you submitted a diagnostic within 10 minutes, the reps can refer to the diagnostic when they’re open. It should, I expect, have an indication of what had caused this issue, be it network related, software related, or hardware related. 

Or source related.

It is most helpful if you submit the diagnostic while an event is in progress, however, some useful data might be available if you submit immediately after stopping noise. With respect to subduing the noise while you submit a diagnostic, placing the unit under a pillow or mattress will help.

Curious to see if anyone has found a solution for this, since its happening to my Roam now too. Currently this is the only thread i can find on the internet which describes the same problem. I’ve tried resetting it, but the noise still comes back after some time. The difficult thing is, that the noise comes at random. So there's no reference to what might trigger this. Hopefully someone found a solution, since this makes the Roam difficult to use.

Just happened to me again. Happened the other day too, also shut off for a while (I didn't have to turn it off myself) but it seemed to have happened both times when it reached around 15% battery. One time was on Bluetooth only and now it was connected to my home. Send a diagnostics just in case. 

Make sure you call in, so that they look at that diagnostic. If you don’t, it won’t be looked at, as detailed in the Diagnostics - How do they work? thread.

Sweet baby Jesus, mine just did this too and it brought me to this forum. I had to wrap it in a towel to save my hearing. This is downright dangerous. Depending on where you’re at when this product decides to ATTACK you (like one person above who was in an *operating room*)…. I will absolutely think twice before ever buying another Sonos product again. And how can I feel confident this won’t just happen again? So much for relaxing and listening to music! Sonos FINALLY updated their app recently which gave me some hope… and now this. Thanks Sonos…