Is it possible to revert to an older OS version?

Downgrading to an earlier macOS version is an unsupported process that is not to be taken lightly.  The word downgrade is not even in Apple's vocabulary.

In any case, a Mac cannot be downgraded to a version of macOS that predates the release of that computer. That is to say if the Mac shipped with Tahoe 26, it cannot be downgraded to Sequoia 15. 

Otherwise, downgrading requires that you: 1) backup your files, 2) - optional but recommended - download the older OS and create a bootable USB installer, 3) boot in recovery mode to erase and reformat the startup drive, 4) download and reinstall the older OS, 5) reboot and step through the Setup Assistant to create and setup a new User Account, and finally, 6) restore your files from a backup. Additionally, it is possible that your Mac’s firmware has also been updated when the newer OS was installed, potentially requiring that you use a second Mac to Revive or restore your Mac in DFU mode.

Apple is not in the habit of making downgrading its devices easy or even possible, as in the case of the iPhone and iPad.  Apple's "Erase and Reset to Factory Settings" feature of macOS doesn't even erase the OS from the computer, in fact. It only erases the user settings and data and does require one to create a new user account.  

It's much easier to work through any problems you are experiencing in the newer version than trying to downgrade.

1) Backup your files to an external disk with  Carbon Copy Cloner  or  SuperDuper! 

2) Download the older macOS version and create a bootable USB installer for it on a USB flash drive. This is insurance in case the Mac can’t/won’t boot in recovery mode.

3) Start up your Mac in macOS recovery mode. 

• Launch Disk Utility and format the internal drive. Select the GUID partition scheme, the APFS format and name the drive “Macintosh HD”.  This step will erase all of your stored data from the drive. Quit Disk Utility.

• Launch Reinstall macOS… and follow the prompts to select the destination drive - Macintosh HD - and begin the reinstall process. Reinstall macOS  

• If Reinstall macOS… doesn’t offer the OS you want, you can now use the bootable USB installer that you created.

4) Restore items backed up with Time Machine on your Mac from the backup made before your upgrade to Tahoe, or restore your files from the CCC or SuperDuper! backup you made before you started the downgrade.

Hint: It’s easier and wiser to work through any problems you are experiencing than trying to downgrade macOS. I cannot emphasize this enough.

nkfarlow wrote:

Thanks for your reply and detailed instructions. It does sound like a hassle! I haven't experienced any improvements, only an issue, since two updates ago, and now my iMac wants to do another update. I've posted about my issue before and was told it's a known issue. No solutions were offered.

Any fix to a known issue would come from an update. The version your Mac wants to update to is likely 26.3.1, so the would be the first step to see if the update has solved the problem for you. I did see in your previous post that the other user who had the problem with music stopping found it was resolved in 26.3, but it does appear that is the version you are currently using.

• I haven't experienced music stopping on any of the OS 26 versions, but I only have it playing about 4 hours at a time. Is it possible that music is being played on another device that is signed into your account? Check your devices logged into your account by going to  > System Settings > [name on top], and scroll to the bottom. If any of the devices listed there starts playing music, it will be paused on your device.
• Are you using AirPlay to play music to an external speaker? If so, see if the same thing happens when not connected to the speaker.
• On the other hand, do you have any AirPods or external bluetooth speaker that the audio output is connecting to? My Mac will auto connect to my AirPods and if Apple Music is playing and I put in my AirPods, then the music is paused on my Mac.

• Did you update to the latest version of MacOS (26.3.1)? I was under the impression that it had not been applied yet.
• Do you have a VPN or Antivirus software installed?
• Does the same thing happen when playing music locally in your Library or is it only when streaming?
• Does the same thing happen when Bluetooth is turned off?
• Have you tried starting up in Safe Mode to see if the same thing happens? When doing this it will take longer to boot and you should see "Safe Boot" on the screen. After testing, restart again normally to exit Safe mode.

Startup in Safe Mode

• If the problem does not occur in Safe Mode, then post the free EtreCheck report that can be used to identify possible conflicts.

Post EtreCheck report using Additional Text option

• Have you tried connecting your Mac directly to the router instead of using Wifi?
• Are you using a Firewall that is blocking ports?

Personally I would troubleshoot further or even contact Apple directly. It does appear there is something unique in the setup, otherwise everyone would be reporting the same thing and that is not the case. That same issue has been reported previously going back to 2019 and the resolution did not always result in an OS update. The only time I have seen where an update resolved the problem was from the user on your other post who said it was resolved in 26.3, but that is apparently not the case for you.

Contact Apple

If it were always "much easier to work through any problems," then this thread wouldn't exist. And thank goodness for this thread, because the Tahoe Music app has driven me back to Sequoia after months of trying to work through its problems.

So, thanks for the help, everybody!

,,,,,,,

Thanks