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How to downgrade macOS 27: Roll back Golden Gate to Tahoe

Macworld Upgrading macOS doesnt always go as planned. A new release might slow down your Mac, break essential apps, introduce bugs, or simply change features you rely on. If youre wishing you could go back to the version you had before, the good news is that you can downgrade macOS. While reverting a macOS update is generally easier than downgrading an iOS update , its not as simple as installing macOS . It is a multi-step process that typically requires wiping your Macs internal drive, as Apple does not allow installing an older version of the operating system directly over a newer one. Because you need to erase your Macs internal drive before you can reinstall an older version of the operating system, your data must be backed up first. The exact process depends on whether you created a backup before upgrading macOS. In this guide, we run through the safest way to revert to an earlier version of macOS, explain what works (and what doesnt), and help you choose the best method for your situation. Note: macOS 27 Golden Gate runs only on Macs with Apple silicon, so the main Golden Gate-to-Tahoe instructions in this article are for Apple-silicon Macs. We cover older Intel Macs separately below for readers using this guide to downgrade an earlier version of macOS. Can I downgrade from macOS Golden Gate to Tahoe? Yes, it is possible to downgrade from macOS Golden Gate (macOS 27) to macOS Tahoe (macOS 26), but the process is complex and requires you to completely wipe your Macs data and install the older version of macOS. Before you begin, confirm that your Mac can run Tahoe . A Mac cannot install a version of macOS older than the version it originally shipped with. A Mac introduced with Golden Gate may therefore be unable to run Tahoe, even if another Mac with a similar processor can. Check Apples compatibility information before erasing anything. You need the following: A backup : You will have to wipe your Mac, so you need to have a backup of your data. The correct macOS version : You need to download the full installer for the version of macOS you want to install. An external drive : You need to create a bootable installer of macOS. Apple says a 32GB USB drive has more than enough space for any macOS installer; 16GB is sufficient for most older versions. A reliable internet connection : The installer may need to download firmware and other information specific to your Mac. Follow these steps, which we explain in more detail below: Back up your Mac. Check that your Mac can run macOS Tahoe. Get the Tahoe installer. Create a bootable installer. Shut down your Mac and start it from the bootable installer. Erase the internal startup volume using Disk Utility. Install macOS Tahoe. Set up the Mac and recover compatible files from your backup. Can I downgrade macOS 27.1 to iOS 27.0 (or macOS 26.7 to 26.6)? Foundry Apple issues multiple point updates throughout the year. If something breaks following an update, you may want to return to the previous releasefor example, by downgrading from macOS 27.1 to macOS 27.0. The same principle applies to subsequent Golden Gate updates. Rolling back a point update can be more difficult than downgrading from Golden Gate to Tahoe because you need the full installer for the exact earlier release. Apple generally offers only the latest installer for each major version of macOS, so the macOS 27.0 installer may no longer be available after macOS 27.1 has been released. However, you may be able to obtain the required version of macOS using Terminal. We detail how to do this below (see step 2). As of September 2026 there were various version installers of Tahoe and Sequoia available using this method. A Time Machine backup cannot provide the missing installer or reinstall the earlier operating system. If you have access to the appropriate full installer, you can create bootable installation media and follow the erase-and-install process described below. If Apple no longer offers that release and you did not retain its installer, an ordinary downgrade may not be possible. Downgrading macOS to an earlier version: Step-by-step guide The steps below will help you revert to macOS Tahoe. Before you start, remember that you must wipe your Mac and perform a clean installation of Tahoe. Reminder: This will erase your Mac, so make sure you have a backup of important files before continuing. Before you begin: Back up your Mac Backing up your Mac is the most critical step before a downgrade because the process requires erasing your startup drive, which removes all locally stored data. If you dont already have a backup, you will need to make one. Time Machine is the standard backup method for most Mac users, but restoring data from a newer version of macOS to an older one can present problems. A Time Machine backup made under Golden Gate may contain Photos libraries, Mail databases, settings, application data, and versions of apps that are not compatible with Tahoe. A backup made while the Mac was still running Tahoe is therefore the safest one to use. However, it wont contain files created or changed after the upgrade to Golden Gate. If Golden Gate is still working, make a separate copy of every irreplaceable document you have created or modified since upgrading. Before recovering data from a Time Machine backup, you must install Tahoe on the Mac. You can then use Setup Assistant or Migration Assistant to transfer compatible accounts, apps, settings, and files from the backup. If you store documents in iCloud Drive or use iCloud Photos, fully synchronized items should become available again when you sign in to the same Apple Account after reinstalling macOS. Before erasing the Mac, check iCloud.com or another Apple device to confirm that important documents, photos, and videos have uploaded successfully. Remember that iCloud is a synchronization service rather than a separate backup, so keep an independent copy of irreplaceable files where possible. To ensure your data remains accessible after you return to an older version of macOS, consider these backup strategies: 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 ChronoSync , Get Backup Pro , SuperDuper , or Carbon Copy Cloner can create a separate copy of your data. Do not assume that a clone created under Golden Gate will be bootable on your Mac or that it can replace the Tahoe installer. Cloud synchronization: Make sure cloud storage services such as iCloud , Dropbox , OneDrive , or Google Drive have finished synchronizing. Do not assume that every apps 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. For more help read: How to back up a Mac. 1. Check that your Mac can run Tahoe Step back to Tahoe, if your Mac can run it. Thomas Armbrster The version of macOS you install must be compatible with your Mac. A Mac that was upgraded to Golden Gate can be returned to Tahoe only if that model supports Tahoe. A model that first shipped with Golden Gate cannot be downgraded to Tahoe. For example, Apple announced the M6 Mac mini before Golden Gate was released, but the Mac did not ship until afterward and requires macOS 27. Always check that your model supports the older operating system before erasing the Mac. Check our lists of Macs compatible with Golden Gate and Tahoe . 2. Get the macOS Tahoe installer You can download old versions of macOS from Terminal, if they arent on the Mac App Store. Foundry The next stage is to get the full installer for the version of macOS you require. In most cases, the Mac used to download the installer must itself be compatible with the version of macOS you require. For this downgrade you need the Tahoe installer, not the Golden Gate installer. For Tahoe and earlier installers, see our guide to downloading older versions of macOS . Normally Apple makes older versions of macOS available to download from the Mac App Store. For example, you can get Sequoia , Sonoma and Ventura this way. However, as of September 2026, Apples hasnt made Tahoe available from the Mac App Store. We expect that it eventually will do so, but in the meantime the best way to get the Tahoe installer it to use Terminal. Terminal method Open Terminal. Type in the following: softwareupdate --fetch-full-installer --full-installer-version [number] You need to include the relevant version number. For example softwareupdatefetch-full-installerfull-installer-version26.6.2. To see which installers Apple currently offers for that Mac, run: softwareupdate --list-full-installers If Terminal reports that the update was not found, Apple may no longer offer that exact release, or it may not be compatible with your Mac. When the download finishes, the full installer will appear in the Applications folder. Quit it if it opens automaticallyyou need to retain it to create the bootable installer. In each case of the above screenshot the macOS installer is listed as Deferred: No, which means the installer is still available. Mac App Store method Open the Tahoe download link on a compatible Mac. If the Mac App Store does not open, close it if it is already running and try the link again in Safari. Click Get. Software Update should open and offer to download Tahoe. Click Download and confirm that you want to download the older operating system. If the installer opens automatically after downloading, quit it. You do not want to run it directly over Golden Gate. The installer will appear as an app named Install macOS Tahoe in the Applications folder. As noted above, downgrading from one Golden Gate point release to another requires the full installer for the exact earlier release. Because Apple generally offers only the latest installer for each major version of macOS, the version you need may no longer be available unless you previously downloaded and retained it. A Time Machine backup cannot provide the missing installer or reinstall the earlier operating system. 3. Create a bootable Tahoe installer Once you have it, you can use the bootable installer of Tahoe to downgrade your Mac. Foundry You cannot install Tahoe directly over Golden Gate. To install an older version of macOS, you need to create a bootable installer containing the Tahoe installation files. You will need a USB flash drive or other external volume. A 32GB drive is recommended, although 16GB is sufficient for many older macOS installers. The drive will be erased during the process. Follow our complete guide to creating a bootable macOS USB installer , selecting the instructions and createinstallmedia Terminal command for macOS Tahoe. The Tahoe command is: sudo /Applications/Install macOS Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume Replace MyVolume if your external drive has a different name. Make sure --volume contains two ordinary hyphens, not an en dash or em dash. The linked guide explains how to prepare the drive, run the command and troubleshoot the creation process. 4. Start your Mac from the bootable installer You want to choose the Install macOS Tahoe option, similar to whats shown. Foundry With the bootable Tahoe installer ready, the next step is to start your Mac from it rather than from the internal drive currently running Golden Gate. Shut down the Mac. Connect the bootable Tahoe installer directly to the Mac. Press and hold the power button. Continue holding it until the startup options screen appears. Select the bootable installer, then click Continue. Connect to Wi-Fi if prompted. 5. Erase the internal startup volume Foundry Warning: This step will permanently remove the local accounts, applications, settings and files stored on the Mac. When the Utilities window appears, select Disk Utility and click Continue. In Disk Utility, choose View > Show All Devices if the internal volumes are not visible. Select the internal macOS startup volume, usually named Macintosh HD. Click Erase or Erase Volume Group, as offered. Use Macintosh HD as the name and APFS as the format. Confirm the erase and wait for it to finish. Quit Disk Utility to return to the Utilities window. Erase All Content and Settings is not, by itself, a downgrade tool. It removes data and settings while retaining the installed operating system. To replace Golden Gate with Tahoe, you need to erase the startup volume from the bootable installer environment and then install Tahoe. 6. Install macOS Tahoe Finally, you can get Tahoe back on your Mac. Foundry With the internal startup volume erased, you can now install Tahoe from the bootable installer. In the Utilities window, select Install macOS Tahoe and click Continue. Follow the onscreen instructions. When asked to choose a destination, select the newly erased internal volume, normally Macintosh HD. Keep the Mac connected to power and the internet while installation completes. It may restart several times. 7. Set up your Mac Foundry After Tahoe is installed, the Mac will start in Setup Assistant. If you have a Time Machine backup from before the Golden Gate upgrade, you can connect the backup disk and transfer your information during setup. Time Machine can transfer your accounts, apps, settings, and files after Tahoe has been installed, but it does not perform the operating-system downgrade, you need to do that first (as per the steps above). If your only backup was made under Golden Gate, setting up the Mac as new and copying your documents back manually is the safest approach. This reduces the risk of importing an app, database, or setting that requires macOS 27. You can then reinstall Tahoe-compatible versions of your apps individually. 8. Transfer data from your Time Machine backup Once your Mac is set up you can copy your data from your backup. Foundry A backup made while the Mac was still running Tahoe is the best one to use. To transfer its contents during Setup Assistant, choose the option to transfer information From a Mac, Time Machine backup, or startup disk. Connect the backup disk, select the appropriate backup, and choose the accounts, apps, settings, and files you want to transfer. If you have already completed setup: Connect the Time Machine backup disk. Open Migration Assistant from the Utilities folder in Applications. Choose to transfer information From a Mac, Time Machine backup, or startup disk. Select the Time Machine disk and then the appropriate backup. Choose the categories you want to transfer and click Continue. The selected backup will not contain anything created or changed after it was made. Copy those newer documents back from the separate backup you created before erasing the Mac. What to do if the older macOS wont install Check the following: Confirm that the Mac model supports the version you are installing. Confirm that the full installer is in the Applications folder and is named correctly before creating the USB installer. Connect the installer directly rather than through a hub or dock. Make sure the Mac is connected to the internet. Re-create the installer if Terminal says it is invalid or the installation fails repeatedly. Confirm that the internal startup volume was erased as APFS. Installing macOS 27 may also update the Macs firmware. Installing Tahoe later does not necessarily roll that firmware back; a macOS downgrade and a firmware downgrade are not the same operation. Tips to avoid problems and data loss when you downgrade macOS Reversing an upgrade carries a number of wrinkles and pitfalls. Many are caused by changes in file formats and settings between versions of the operating system. If you create a document or work on a file in a newer version of macOS and then try to open it in an older version, it may not work. Where possible, export important documents in standard or widely compatible formats before erasing the Mac. For example, you could export a document as RTF or PDF in addition to retaining its native version. Take screenshots of preferences and settings Whenever you perform a clean installation of macOS, its a good idea to take screenshots of custom settings in apps and System Settings. That makes it easier to re-create them later. Make a note of account details for anything you set up while running the newer operating system. Export bookmarks if they are not synchronized, and make sure you have access to application installers, subscriptions and license codes. Synchronize cloud services If you use Dropbox, OneDrive, Google Drive or another cloud storage service, make sure synchronization has completed before starting the downgrade. Files visible in a synchronized folder may not have finished uploading. If you use Gmail, iCloud Mail or another IMAP service, make sure recent mail and drafts have synchronized. If you use a POP3 account, manually back up locally stored mail before erasing the Mac. Finally, keep the Golden Gate backup intact until you have confirmed that Tahoe starts correctly and that all essential documents have been recovered. Do not erase or repurpose the backup drive merely because the downgrade appears to have completed. Downgrading an older Intel Mac Golden Gate does not support Intel Macs. These instructions are for if you want to downgrade an earlier macOS release on an Intel Mac. Intel Macs start from a bootable installer by holding Option (Alt) at startup. Macs with the Apple T2 Security Chip may also need Startup Security Utility configured to allow booting from external or removable media. See our bootable macOS installer guide for the complete Apple-silicon, Intel and T2 instructions. An Intel Mac may also be able to use Internet Recovery. Start it while holding: Shift-Option-Command-R to offer the macOS that came with the Mac, or the closest version still available. Option-Command-R to offer the latest macOS compatible with the Mac. Command-R to reinstall the current version. Internet Recovery cannot install a version older than the one the Mac supports, and the exact version offered can vary.

16 Sep 2026 6:49 pm