My iMac won't stay awake when my Sonos is playing since update to 5.4

It sounds like your Mac is set to automatically log you out after a period of inactivity. Open System Preferences from the Apple menu in the top-left corner. Open the "Security & Privacy" preference pane. Click on the "Advanced..." button in the bottom-right corner. You may need to unlock the pane using the padlock icon in the bottom-left corner. I think you'll find "Log out after XX minutes of inactivity" ticked. Untick it. Good luck!

I just checked. That box wasn't ticked. Issue remains unsolved. Thanks for trying though!

That would make the connection stay alive. But I want the computer to sleep when not in use like it did before. I don't want my computer to always be awake wasting energy for no reason. It should stay awake when Sonos is accessing the library and sleep when not in use. This is how it worked in all version prior to to 5.4. I've been using Sonos in this exact setup for over 2 years now. No issues with this until the new update.

That would make the connection stay alive. But I want the computer to sleep when not in use like it did before. I don't want my computer to always be awake wasting energy for no reason. It should stay awake when Sonos is accessing the library and sleep when not in use. This is how it worked in all version prior to to 5.4. I've been using Sonos in this exact setup for over 2 years now. No issues with this until the new update.
On previous version (havent been able to confirm) when adding the music library you had the option " Allow Sonos to set computer's sleep setting to never" in essence what Max P advices, just a different way of doing, my guess is that this setting has been reset, if the library is not too large and you have time on your hands, remove it and add it again! When prompted make sure the box is ticked

As mentioned in my original post, I know I can make the connection stay by adjusting my computer energy saver settings so the computer never sleeps. That is not an acceptable solution. My computer needs to sleep when not in use. I don't need the extra wear and tear on the hard drive and processors and the extra energy usage if I'm not using my computer. That is the whole point of having energy saver settings.

And I didn't update my Mac since before I updated the Sonos controller app. The only thing that has changed between when it was working properly and not working is the Sonos App controller version. It changed immediately after updating from 5.3 to 5.4. Why?

But the harddisk needs to be accessible and spinning for you to access the music that is stored on the harddisk, so your Mac cannot go to sleep! You can let the display go to sleep, this is what we are trying to say, if the harddisk goes to sleep, the music will stop! Does that make sense? The sonos components do not store the songs.

I think you are missing my point. I don't want it to sleep while playing music. I want it to stay awake while playing music. However, when not playing music, the sleep settings should kick in. This is how it operated in all versions prior to 5.4. What changed in 5.4? And why? By 'not in use' I also mean not being used by sonos. I understand that the computer needs to be awake to access the music library. That's the whole issue. It's not staying awake. It used to behave similar to iTunes. If I am playing music in iTunes, the sleep settings won't kick in. When I stop playing music, the timer starts for the sleep settings. I just want it to go back to this so I don't have to have my computer awake 24/7 unless I manually sleep it.

There is no way the Sonos system has ever controlled the sleep settings on your Mac to keep it awake when Sonos needs it.  That is why the music library setup still does ask if you want to set the hard disk never to go to sleep - because it has no way of managing it thereafter.  Nothing in this respect is different in 5.4 than in any previous version.

I think you are missing my point. I don't want it to sleep while playing music. I want it to stay awake while playing music. However, when not playing music, the sleep settings should kick in. This is how it operated in all versions prior to 5.4. What changed in 5.4? And why? By 'not in use' I also mean not being used by sonos. I understand that the computer needs to be awake to access the music library. That's the whole issue. It's not staying awake. It used to behave similar to iTunes. If I am playing music in iTunes, the sleep settings won't kick in. When I stop playing music, the timer starts for the sleep settings. I just want it to go back to this so I don't have to have my computer awake 24/7 unless I manually sleep it.
Thanks for the reply, John. However, I am going to have to respectfully disagree. Although I wouldn't say Sonos was ever "controlling" the sleep settings on my computer. I would say that Sonos impacted the sleep settings in relation to how the sleep settings recognize when the computer has gone truly "idle" and, thus, starts the timer to go to sleep at whatever interval has been selected in the energy saver settings.

In prior controller versions, the Sonos system accessing the files on the hard drive was enough to keep the system from ever going idle. Therefore, when the system went to grab the next file, the connection was still alive and the song played as expected. If I stopped playing music for a few minutes, the computer would idle and the sleep settings would kick in based on the energy settings. If I wanted to start playing music again later, I would have to go wake up the computer before starting again, but it would then stay awake for the entire listening session, assuming i never stopped the playback manually (although the display would always still sleep, which admittedly seems a bit odd now that I think about it. I have both display and computer set to sleep after 1 minute of inactivity and have had it this way since i got my first Sonos component over 2 years ago.)

For some reason since updating to 5.4, the Sonos activity of accessing the files on my hard drive is not enough to prevent the computer from idling. It still will go idle and then after a minute sleep and wind down the hard drives, resulting in the Sonos being unable to connect to my library to play the next track in the queue. However, it will always finish the current song, which leads me to believe there is temporary local caching on the Sonos system for at least the current track, contrary to what afroviking stated in his most recent post. Although I'm not truly sure.

It behaved as described for over 2 years and multiple controller versions. I promise you I am not making things up. Behavior changed immediately after upgrading to 5.4. I'm hard pressed to believe this is merely a coincidence. I'll time machine back to 5.3 and prove it to you if I must.

RIght now I'm just using Caffeine to keep my iMac awake while playing music without altering my sleep settings, but would prefer to find a real solution rather than a workaround. It may seem like a minor issue on the face, but it can have a significant impact on the life of my iMac components and the size of my energy bill.

I think you are missing my point. I don't want it to sleep while playing music. I want it to stay awake while playing music. However, when not playing music, the sleep settings should kick in. This is how it operated in all versions prior to 5.4. What changed in 5.4? And why? By 'not in use' I also mean not being used by sonos. I understand that the computer needs to be awake to access the music library. That's the whole issue. It's not staying awake. It used to behave similar to iTunes. If I am playing music in iTunes, the sleep settings won't kick in. When I stop playing music, the timer starts for the sleep settings. I just want it to go back to this so I don't have to have my computer awake 24/7 unless I manually sleep it.
OK.  I'm sure you aren't making it up.  Whether you are right or not, my certainty that you were wrong was unjustified.  I will keep an eye out for other users having similar experiences.