An older version of the app would probably not work with the newer software on your system…..

Thanks, 106rallye for the reply.  I called Support and they more or less verified your answer. I have an older OS and, the odd thing is that updates - up until Saturday’s debacle - worked just fine. I tried Authorizing the Sonos App in my Preferences (Privacy & Security) and then performed a restart. Still no luck. I’ll probably update the iMac’s OS to Mojave and, down the line, just buy my wife a new iMac.

Thanks again.  Brad

I guess if I would have a favor to ask of Sonos it would be to create a “Smart” installer that would have recognized the incompatibility between my OS and the updated Sonos App and stopped the process instead of installing an app that doesn’t work. If it hadn't been historically successful in the past, I may have just skipped the update.

Note: If anyone else has this issue, I don’t recommend restarting your router and/or resetting your speakers as older threads have suggested. There’s nothing wrong with either of those items on my end. Spotify can still be fed to my system and my TV audio works just fine as does all streaming coming through the router.

In many cases If the players have been updated using another controller, an outdated desktop controller will still continue to function for a few more player updates. Eventually, this trail ends. If you introduce a new SONOS model, I doubt that an outdated controller will continue to work. The S1 controllers are only receiving security updates.

Hi

If you used Time Machine (built-in Apple Backup program) you could restore your system to a date prior to the issue you are experiencing. 

Hint: Time Machine requires an external drive connected to the iMac. If no external drive was used then you don't have a Time Machine backup from which to restore your system.

Hello, buzz… I was using the S2 controller on the older iMac and only reintroduced the S1 app after continual “Quits Unexpectedly” errors during the Sonos installer’s automated relaunch process. Oddly enough, I’d upgraded from Sonos Play 1s to a pair of new Sonos 5s and those worked up until this past Saturday.  I still get TV audio, Spotify audio but, can’t access my iMac’s Sonos library. Oh well.

AjTrek1… I do have a Time Machine backup and could restore the System but, that could open up a can of worms.  I’m gonna take my time to sleuth this one.  I may just update to Mojave and call it good. I know “updating to Mojave” sounds oxymoronic but, we have software on that computer that works perfectly now but, upon updating, may not.  Eventually, Mojave may be only option. Second will be an updated iMac (this one is a 2013 model - aka dinosaur).

I totally get that El Capitan is old. Upon the most recent update, I called in and spoke with someone at Sonos and asked them for a link to the last working version of the S2 software. They did provide me with a link and I was able to install that version and simply ignore the requests to update the software. But one day, the whole thing crashed and installing the version shared with me asks to update the software.

SlamDesi,

You cannot indiscriminately flip between S1 and S2 controllers. The controller must match the system firmware of the “system” that you want to control. If your SONOS units can be downgraded to S1, you’d need to down grade the units, then you could use the S1 controlller.