Any chance you’re running a network extender, or a mesh network? It’s entirely possible the two devices are on separate subsets. 

No, this is strictly a single router, no extenders. But you make a good point, that will probably help someone else.

Hmmm. Can I say ‘wrong answer, please try again’? ;)

That does make it more complex, to be sure. Does the Arc show up...oh, you said it did on an iOS device. Even odder.

First thing would of course to update to the software released this morning, and see if that makes a difference, but my confidence in that solving it is low. 

I’d recommend that you submit a diagnostic from both devices, and then call Sonos and have them compare the two. I would hope that they would reveal what the difference between the two ‘connections’ is. 

I’ll have to download a complete new version of the program then, because this one goes directly to “new system or existing?” when I open it, and all the menu items are greyed out.

And I wish they’d get the S2 program certified by Apple so I didn’t have to deal with all the security warnings. Then again, maybe Apple won’t certify it, which concerns me.

Absolutely nothing wrong with downloading a new version and installing it. There is essentially no data stored on the controller, it is all stored on the computer in the speaker(s).

I didn’t mean to sound like I had a problem with the download. Its just the process reminds me that Sonos is working outside the walled garden for some reason. I just looked on the app store and all the official Sonos apps seem to be gone now, where S1 was still there just last week.

Honestly don’t know, since they work within the garden for the iOS controller. My guess would be it’s more effort, for something that Sonos is reducing emphasis on, but who knows. 

I thought I might have had a solution when I found out the Sonos was plugged into a switched outlet on my power center, but I moved it to an always-on socket and the issue persists. This is odd.

This is frustrating: I spent quite a bit of time on a chat with Sonos. There appears to be no reason at all why the S2 app will not work. My system report for the iOS app shows no flaws, and I have my firewall set properly on the iMac. Of course the S2 app is stalled at “Not connected” so there’s no way to do a diagnostic there. I guess S2 isn’t really ready for prime time.

It is indeed odd, as I have zero issues seeing either of my Arcs from my S2 controllers on three different Macs.

There are more than a few things here that don’t make sense. The error message has no number attached to it, so I can’t look up a response via the error number. The “for information about” part of the dialog points me to the firewall settings page and also the Sonos setup page. But neither of those have any bearing on this since we’re doing the desktop app setup. You have to have a working Sonos sytem for the desktop S2 to have anything to work with in the first place, so why would the desktop S2 point us to the mobile app setup procedures for advice?

Because set up procedures have been removed from the desktop app. It is only a controller for playing music at this point, to do any setup tasks, you must use a mobile device. It has been that way for well over a year, maybe two now. It’s part of the whole ‘Sonos is reducing emphasis on’ that I mentioned above. 

I get that. What I mean is - if you’re trying to connect the S2 desktop to an existing system and it won’t see the system, why is the thing sending you to the new setup page? Obviously its set up or you wouldn’t be trying to add the desktop S2, right?

Ah, I see. I don’t know, honestly. I’ve not run in to this issue on my system, and am not familiar with the code choices made in that case by Sonos. But would agree, not unlike many other ‘error’ conditions, the results displayed are sub-optimal. 

The chat session I got done with was nothing more than repeating back the setup instructions. The rep told me to call them so they could show me how to authorize remote access for them to get in to my computer for further diagnostics. There’s no way in hell I’m ever allowing remote login on my system. And really, what would remote access allow them to do that I couldn’t do myself with a guide via chat?

I gotta tell you Bruce, I’m more than a little suspicious of Sonos at the moment. Between this remote login request and their non-certified Mac app, I am really wondering about them.

I think I’m on the way to figuring this out.

Since you said you had the app running on 3 different Macs, I decided to try one in another room. Its older but its running the current OS. With S2 installed and whitelisted on the firewall, I launched the app. I kept the whitelist open so I could see if anything changed.

I got an odd message that doesn’t show up when I install on the newer iMac: “Sonos would like to use accessibility to control your Mac” or something similar, followed by Deny and Allow. I clicked Allow - which I wasn’t happy about - and I saw a second Sonos icon identical to the first appear in the whitelist.

I told it to look for an existing system, and the Arc came right up and ready to work.

So I have to wonder why am I not getting that question in the other iMac, and since its apparently required for this S2 app to work, how do I get to that question?

Further progress:

I found that the dialog window I was looking for was actually opening the whole time, but over half of it is immediately obscured by the Sonos window upon launch. There is a Deny button but no Allow button - instead it I have a “Open Security & Privacy” button. Doing that merely takes me to the Accessibility pane, with no further instructions. I added the thing to the whitelist in that pane and made sure the box was checked. I went to the Firewall and found no duplicate Sonos icon in the whitelist there. The apps launches like usual and still behaves the same way - it can’t see my Arc.

A final thought occurred to me: my older computer is actually running Catalina, whereas the main system is running Big Sur. What OS do you have installed on each of your three working Macs? Perhaps Big Sur is the issue here.

All my Macs happen to be using the latest version of Catalina. So it could be Big Sur. 

I don’t frequently use the Sonos app on my Macs. Most frequently I use either an iPhone or iPad to mess with my Sonos system, given the neutered capabilities of the desktop versions. Frankly, the only times I fire up the desktop version is to answer questions here in these forums.