How do I downgrade my M2 Mac from golden gate to tahoe.

Reverting to an older major version of macOS is not simple. You need to boot into Recovery OS, erase your internal drive, then install the older macOS, then restore from a backup made prior to the recently applied upgrade*. Even then, the firmware on the Mac may have been updated, meaning potential conflicts and a possible need for DFU mode and a Configurator revive/restore, which would need to be done via another Mac connected to yours. If that sounds complicated and risky, then you're assessing the situation correctly. Also note that in no case can you install a version of macOS that is earlier than the version installed on your Mac when it came out of the box. 

*Regarding the backup, if you want to pick up where you left off on the old version, you really need a backup made before the upgrade. If you do not have such a backup (why not?), then there are alternatives but you must be prepared to accept some work to get back to your normal. If you're in that situation, here are some strategies (and caveats):

• Manual file copying: Copy your most important files, folders, photos, and music to an external storage drive.
• Third-party backup software: Tools for backing up a Mac, such as SuperDuper or Carbon Copy Cloner can create a separate copy of your data. Do not assume that a clone created under the new major version of macOS will be bootable on your Mac.
• Cloud synchronization: Make sure cloud storage services such as iCloud, Dropbox, OneDrive, or Google Drive have finished synchronizing. Do not assume that every app’s data is stored in the cloud, as some applications store data only locally.
• Time Machine: If you have a Time Machine backup from before you upgraded to Golden Gate, you can use it to transfer compatible data after reinstalling Tahoe. When setting up the Mac from the backup, be sure to use a backup date from before you applied the major upgrade. You cannot restore from a backup made post-upgrade, and any changes since the upgrade will be lost.

Part 2 of 2

Downgrading an Apple Silicon Mac to macOS  26  Tahoe 

On Apple Silicon Macs, downgrading to an older version of macOS requires a complete erase of the internal drive. 

You cannot install an older macOS version over a newer one. 

Before you begin, create a complete backup of all your data.

Step 1: Back Up Your Mac

This is the most critical step. Downgrading will erase your Mac's internal drive, so you must back up your files and settings beforehand.

Time Machine is the recommended backup method. Use Apple's built-in Time Machine to create a full backup on an external storage drive. 

Alternatively, you can manually copy all essential files to an external hard drive or another storage location.

Step 2: Create a Bootable macOS 26 Installer

To install the older operating system, you'll need a bootable USB installer.

On a Mac compatible with macOS  26 , download the Install macOS Tahoe app from the Mac App Store.

Connect a USB flash drive with at least 15 GB of free space. 

Open Terminal, which can be found under Applications > Utilities, and run the following command:

Tahoe macOS 26 via Terminal 

sudo /Applications/Install\ macOS\ Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Replace MyVolume with the name of your USB drive.

Step 3: Erase Your Mac's Internal Drive

Shut down your Mac completely. Press and hold the power button until the Loading startup options screen appears.

Click Options, then click Continue. Select Disk Utility and click Continue.

In the Disk Utility sidebar, select your internal drive, typically named Macintosh HD, and click Erase. Enter a new name for the volume if desired and make sure the format is set to APFS. Click Erase Volume Group to erase the internal drive.

Step 4: Install macOS 15 from the Bootable Installer

After the erase is complete, quit Disk Utility to return to the Recovery menu. 

Choose Install macOS Tahoe and connect to Wi-Fi if prompted.

Follow the on-screen instructions and select the internal drive you just erased as the installation destination.

Wait for the installation to finish. 

Your Mac will restart several times during the installation process.

Step 5: Restore Your Data

After macOS Tahoe has been installed and the initial setup is complete, restore your data. 

If you backed up your files manually, copy them back to their appropriate folders.

Important Considerations

Data loss: Any files created or modified on macOS 27 after your last backup will be permanently lost during the downgrade.

Application compatibility: Some applications updated for macOS 27 may not work properly on macOS 26 .

Hardware compatibility: Your Mac must support macOS 26 . A Mac that shipped with macOS 27 and never supported macOS 26 cannot be downgraded.

Firmware considerations: Downgrading to a significantly older macOS version may or may not require a firmware downgrade, which increases the complexity and risk of the process. 

Apple Configurator can be used for more advanced recovery and downgrade scenarios.

As with all macOS versions, you erase the drive completely, reinstall the older macOS, then migrate from a backup made before you upgraded to GG.

You should do all of that by using a bootable USB Installer. You must make the bootable installer on that Mac prior to erasing.

If you do not have a backup made before GG, it will not be easy to restore your data. You will have to move everything manually and reinstall apps that are not bundled with macOS.

Erasing Apple Silicon may leave you with an unusable Mac that will require a DFU reset. That requires the use of another Mac.

Before doing anything, make sure you have a current backup of anything you need to keep. Downgrading from macOS 27 Golden Gate to macOS Tahoe 26 requires erasing the Mac.

Since your M2 Mac is Apple silicon, the most predictable method is to create a bootable macOS Tahoe installer, start up from it, erase the internal disk with Disk Utility, then install Tahoe.

Apple has the Tahoe installer and instructions here: Create a bootable installer for macOS - Apple Support

If Golden Gate was installed as an upgrade from Tahoe, macOS Recovery may also offer the previous version after the disk is erased, but I wouldn’t erase first unless your backup is confirmed.

Part 1 of 2

Part 2 will be covered in a separate reply

Part 1

User Risk Assessment: macOS Downgrade Procedure

Before initiating any downgrade from macOS 26 (Tahoe) to an earlier version such as macOS Tahoe , assess the user’s tolerance for potential risks. The following checklist must be completed before proceeding.

Primary System Dependency

Determine whether the affected Mac is the user’s primary or only computer.

If the user cannot function without this system for several days in the event of a failed downgrade, the risk level is high.

The downgrade should be postponed or avoided until proper contingency measures are established.

Availability of a Secondary macOS System

Confirm that the user has access to another Apple computer currently running macOS 26

This secondary system must be capable of performing a Revive or Restore operation on the target Mac’s firmware if required.

Lack of a secondary Mac significantly reduces the ability to recover from firmware corruption or boot failures.

Firmware Compatibility and Secure Enclave Risks

Be aware that upgrading to macOS 27 Golden Gate likely includes a firmware update affecting the logic board and Secure Enclave Processor (SEP).

Downgrading to an earlier version (e.g., Tahoe) may or may not introduce firmware mismatch issues, leading to instability or loss of functionality.

Backup Integrity and Recovery Preparedness

Verify that the user has at least three complete backups created before the macOS 27 Golden Gate upgrade.

Implement the 3-2-1 Backup Strategy:

3 total copies of essential data

2 different backup methods or storage media

1 copy stored offsite (for protection against natural or human-caused disasters)

Each backup should reside on a dedicated, single-purpose external drive.

For enhanced backup and cloning capabilities beyond Time Machine, refer to:

🔗 https://bombich.com

Recommendation Summary

If the user answers NO to any of the above questions:

Downgrading the Mac is not recommended.

Proceeding without proper contingency plans, verified backups, and recovery tools may result in:

Data loss

Firmware corruption

Secure Enclave failure

Complete system inoperability

Barney-15E wrote:

Erasing Apple Silicon may leave you with an unusable Mac that will require a DFU reset. That requires the use of another Mac.

When I got MPB M5 I fiddled with it by trying to erase its internal device but a kernel process (Tahoe) prevented erasing the whole device which is possible in Intel Macs.

I then prepared a bootable USB macOS installer via the Terminal but then the Disk Utility seemed to be accessed via internal or Internet Recovery anyway and erasing the internal device was not possible.

But it is possible to erase the internal Container or Volume with a desired name. When then exiting Disk Utility the Mac prompts to connect to Wi-Fi and is then Activated. Then install macOS.

But the simplest and recommended way to start from scratch might be:

Reset to factory settings: General > Transfer or Reset > Erase All Content and Settings... > Join Wi-Fi, Activate Mac > ...

BTW I then also tested MBP M5 DFU Restore and it worked OK from Mac mini 2018 Intel Sequoia Finder.

BTW2 I have also tested installing Tahoe and Golden Gate to external volumes and it works OK. But cloning a bootable volume with Carbon Copy Cloner has never worked and it tends to render any other external volumes un-bootable. That can be fixed by applying macOS installer to that volume but it is less time consuming and robust to just un-learn old habits, bite the bullet, and use the macOS installer so it in its kosher way updates the boot volumes.

In the old Intel Mac I always dual booted via Option-boot, but in MBP M5 a detour to System Settings > Startup Disk is faster (since shutting down the MBP M5 and waiting for the boot options panel is not necessary) and more robust because it seems to bless the boot volume, if necessary. Lately I noticed that Startup Disk seems to fail to bless volumes on the same container so a detour to internal boot or maybe another partition boot is then necessary.

Reset to factory settings: General > Transfer or Reset > Erase All Content and Settings... > Join Wi-Fi, Activate Mac > ...

But, that will not allow you to reinstall a previous macOS version. You must remove the start-up volume. which may be possible in disc utility, when started from the bootable USB installer.

If you have enough space on the drive, you could create a new APFS volume and install the OS there. Then, while booted from that newly installed OS, you can probably remove the Golden Gate volume.

I have tried neither of those. I have only done it the way I originally noted on an M1 mini in order to revert back from a beta.

I just downgraded back to Tahoe 26.7 today and everything is great again! After a week of the wrong apps opening at random I couldn't stand it any more. I didn't need a local Siri AI, and the sluggishness in Golden Gate was unbearable even after Siri AI installed and indexing completed. Golden Gate took over 3 minutes to fully boot and with all the random wrong apps opening and general sluggishness I thought I was running Windows 11. Golden Gate is not ready for prime time. By the way I'm running on a very fast 2024 M4 Mac Mini with 32 Gb RAM and a 2 Tb internal SSD.

Michael Brooks1 wrote:

Golden Gate took over 3 minutes to fully boot and with all the random wrong apps opening and general sluggishness I thought I was running Windows 11. Golden Gate is not ready for prime time. By the way I'm running on a very fast 2024 M4 Mac Mini with 32 Gb RAM and a 2 Tb internal SSD.

FWIW, I'm running Golden Gate on an M3 iMac with 16GBs RAM and 1TB drive and have none of the issues you mention.

p.s. I am running Siri AI.

I never bothered to check boot up times but I just checked my M1 MacBook Air, running Golden Gate, also with 16GBs RAM & 1TB drive. It took just over 40 seconds to "fully boot". I can only assume there was something wrong with your install of macOS 27 or something already installed that caused your issues.

p.s. Also running Siri AI on the MBA.

Michael Brooks1 wrote:

I just downgraded back to Tahoe 26.7 today and everything is great again! After a week of the wrong apps opening at random I couldn't stand it any more. I didn't need a local Siri AI, and the sluggishness in Golden Gate was unbearable even after Siri AI installed and indexing completed. Golden Gate took over 3 minutes to fully boot and with all the random wrong apps opening and general sluggishness I thought I was running Windows 11. Golden Gate is not ready for prime time. By the way I'm running on a very fast 2024 M4 Mac Mini with 32 Gb RAM and a 2 Tb internal SSD.

Your system may not be ready for Golden Gate, macOS 27 is generally fine. There are some minor bugs, things with Mission Control and screen savers. But few people are seeing performance impacts, and if you are it's because of 3rd party software you have chosen to install that is not compatible with Golden Gate. When that happens, either the software doesn't work (more common) or the system has issues (less common but it happens, especially with system extensions).

Personally, my 16" M4 Pro MBP (48 GB memory, 2 TB storage) is running just fine on Golden Gate. My other Mac (a 16" M1 Pro MBP, 16 GB memory, 1 TB storage) is still on Tahoe because that's my work Mac and there is one piece of software on which I am waiting for a macOS 27 compatibility update.

dialabrain wrote:

I never bothered to check boot up times but I just checked my M1 MacBook Air, running Golden Gate, also with 16GBs RAM & 1TB drive.

Not sure what I was thinking. The MBA has a 512MB drive.

PreCognition wrote:

Since your M2 Mac is Apple silicon, the most predictable method is to create a bootable macOS Tahoe installer, start up from it, erase the internal disk with Disk Utility, then install Tahoe.

FWIW when my MBP M5 was new and I had good backups I did a test (I was fully prepared for DFU...):

I know M Macs use internal device for the early boot process so I tested if I could erase it, and surely enough, Kernel process (Tahoe, and Golden Gate when I later again tested this) prevented erasing the internal device which is possible in Intel Macs. I then in GG erased the internal APFS container which worked (erasing the APFS volume is another option which I did not test):

BUT then the Mac could not boot anymore "because there was no admin user" no matter what. I did not disable Find My Mac before testing which might explain it. I could boot to Recovery mode but that did not help with the "no admin" issue.

So in the end I used my old Mac mini 2018 running Sequoia and used its Finder to DFU Restore the MBP M5 to factory settings Golden Gate.

After using Golden Gate for a week, moving back to Tahoe would be an upgrade... Sequoia as well... heck, I still miss Mountain Lion - most efficient and smooth-running OS they ever made; Apple OS's have been in downfall ever since.

Anyway, GG has huge lag in opening programs, and the imperative 'click and select multiple files' in finder has been deprogrammed by some 'genius' who thinks they know better than we do what we want. That one's big enough to return this POS and finally try something new... Linux probably (as if there's anything else), as my home is a Gates Free zone.

I'll give it another few days and it will more than likely be returned. GG has zero improvements over Sequoia - literally... prove me wrong. My 19' MBP running Sequoia blows this 23' MBP running Golden Gate away in every single possible aspect. I've yet to find one single thing about it that's been improved.

Anyway, GG has huge lag in opening programs, and the imperative 'click and select multiple files' in finder has been deprogrammed by some 'genius' who thinks they know better than we do what we want.

I have neither of those problems on two Macs. They weren’t laggy even on the first beta releases. I haven’t noticed any difference at all in selecting files.

There were a few posts about dragging files in List view. Something about the icon vs name label. Whichever one you now have to click I always did before so I didn’t see any difference in os behavior.

If the problem you have selecting files is not that List view difference, you might want to look at third-party system modifications, especially mouse drivers.