Is your network a stand-alone router/modem or a Mesh with satellites (used to extend the range).

Stand alone WiFi 6 router. No issues throughout home with any devices. 

I should say our Sonos system used to be on a different WiFi network - which I needed to change (another unnecessarily cumbersome and frustrating process but I did it). My wife deleted her S1 app with the legacy system setup, reinstalled it and is only connected to the new WiFi network. Again, her phone cannot find the existing system. 

Why are you downloading S1 app? Your products per your profile indicate they are S2 (Sonos App) compatible.

Because S2 app “sees my system” and can’t connect to it (gives me an error it isn’t compatible with S2). S1 setup works after having reset each speaker and “downgraded”. Entire setup is clunky. 

Are you able to use Sonos on your device and if so what app are you using (S1 or Sonos App).

Yes, S1

I attached my S2 experience. System works for me using S1. 

Have you used the Compatibilty Check Tool in the S1 app to manage the upgrade to S2? My money is on not.

https://support.sonos.com/en/article/update-to-the-latest-sonos-app-using-the-s1-controller

Still irrelevant to the S1 issues I’m experiencing unless you’re asserting S2 will magically solve all (my money is on not). 

I think you will successfully add your wife to the system if you upgrade to S2 as a starting position. I didn't claim it would solve all your problems, or end world.poverty

No need to be sanctimonious. This sad excuse for software is my biggest problem right now. Tell me I have to factory reset all speakers again because I didn’t follow a ridiculous compatibility tool sequence?

But moving on, is the S2 app on your wife's phone? If so I suggest she uninstall it. Either way she should uninstall the S1 app then reinstall.  Does she get an option then to connect to existing system? 

Are all your speakers on the latest version of the S1 firmware?

She doesn’t have S2 downloaded, has uninstalled/reinstalled S1. When going to connect to existing system, it is not found. 
 

How do I check the firmware versions for each speaker?

System settings, System updates, check for updates

The Graphic you sent suggests the app installed on that device is the Sonos App (S2).

Separately, having not used your compatibility check tool initially or in the correct sequence, how can I get my speakers to be compatible? 

It’s greyed out now. Updating downloads S2 which produces the same error as the one I posted above.

I already mentioned S1 works

Oooh it does Indeed

S1 and S2 are installed on my device. S1 works. Having S2 installed or not has no bearing on my problem. 

My best guess is that te compatibility checker is greyed out because it has already been run and upgrade to S2 refused (which is entirely your prerogative, of course. 

But as you say that's now neither here nor there.

OK...are you running both S1 and S2 setups?

No, S1 only. I don’t have S2 installed. 

OK...do you have a Bridge or Boost installed? If so remove it.