There’s no reason why you can’t add an S1 device from scratch, but first of all, what lights are you seeing on your missing Play:5? …and rather than just cabling your Play:5 to the router, what happens if you first cable a Play:1 to your router and reboot the Play:5 and then try that either wired to the router aswell, or try it wireless?

For future reference: your Play:1 is S2 capable, so your statement about none of your devices supporting S2 is not true. This might help if you need new speakers.

Hi Ken, thanks for helping!

Continuous white light on the missing Play 5.

Also noticed in the app (settings/system/my system) that I can see the missing Play 5 in the list, even if no room name is indicated. I cannot take any action in here and not sure if it means that play 5 is currently detected or if it's a sort of historical connection.

I don't believe I can add any new product from scratch because the "add a product" is greyed out. I've read it's because my Android version (6.0.1) is too old..

I'm going to give your suggestions a try and share the results.

Hi 106rallye.

Thanks for the info. The way I am limited is S2 doesn't seem to be available for my device (oneplus one running on Android 6.0.1, latest available OS).

Yes you are limited by the older android OS, but if you do ever update that mobile, or perhaps borrow a newer device with Android 8.0 or higher, then it will work to install S1 devices from scratch, albeit that may not actually be needed at this stage - see this link:

https://support.sonos.com/s/article/4875

Try first cabling a Play:1 then cable the power-cycled Play: 5 and fully close and re-open the App to see if the Play:5 returns. If it does, then see what happens when you remove the cable and try to run the speaker on a wireless connection.

No luck with any of the suggestions..

I'd make a diagnostic and call Sonos tomorrow.