Choose which ‘system’ you want to keep. 

Follow the instructions in the factory reset FAQ to reset the ‘other’ speakers.

Use the ‘add a device’ function when connected to your ‘keeper’ system to re-add your other speakers. 

Note, however, all stored data (playlists, services, etc) will be deleted from the speakers you reset. 

One further note, now that I think about it.

There are two ‘sets’ of speakers. The older speakers, which don’t have either fast enough CPU or enough memory, have to stay on the S1 operating system. PLAY:5 gen 1s come to mind, as well as some CONNECTs, I think there are others that are S1 only. See more information at this link. 

There are some speakers that can run either S1 or S2. Ones that come to mind right now, but not a full list, are PLAY:1s, PLAY:3s, and PLAY:5 gen 2s, but there are others. 

All the ‘newer’ speakers are S2 only. Again, see the previous link. 

Thanks.  Very helpful. 4 speakers back in 1 system.  Just one speaker causing a problem    
 

it is a Sonos 1.  Second Gen.   serial number underneath is model S13.  have factory reset.  It recognises it but can’t complete set up. 

amazingly I got an orgInal One successfully reset up as part of this but this one is causing me problems. Any ideas appreciated.  Potentially too old?  

There is no Sonos 1. Just a Sonos PLAY:1 and a Sonos One, of which there have been two generations. I wouldn’t think either would be too old, I’m running both types under S2 right now.

It does seem like there is either something wrong with the speaker, or something wrong with the app. I’d recommend you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Thank you

Just tried to call the helpline and there is a 2hour plus wait time and they close in an hour.  Is there a good time to call the help line?