You can install macOS 27 Golden Gate beta on a second APFS volume so it runs alongside macOS 26 Tahoe on the same Mac. When you are done, you can switch between the two operating systems at startup and evaluate Golden Gate’s changes without touching your Tahoe installation. The only prerequisites are an Apple Silicon Mac (M1 or newer), at least 40 GB of free disk space to accommodate the roughly 17 GB installer and the new volume, and enrollment in Apple’s developer beta program.
The dual-boot approach matters because there is no in-place downgrade from Golden Gate back to Tahoe. Once you overwrite your existing volume with Golden Gate, there is no undo option. Installing onto a separate APFS volume is the only safe way to try the beta while keeping your stable Tahoe workflow intact.
Before you start
If you are on one of the Intel models excluded from Golden Gate, specifically the MacBook Pro 16-inch 2019, MacBook Pro 13-inch 2020 (four Thunderbolt 3 ports), iMac 2020, or Mac Pro 2019, this guide does not apply to you, and your only option is to stay on Tahoe.
Back up your Mac with Time Machine before doing anything else. If you use a Time Capsule for Time Machine backups, be aware that Golden Gate requires SMBv2 or SMBv3, and Time Capsule hardware is no longer compatible in its stock form. Verify your backup destination before you reboot into Golden Gate for the first time.
Step-by-step installation
-
- Open Disk Utility. You can find it in Applications > Utilities or by searching with Spotlight. Make sure you are running this from your existing Tahoe installation.
- Select your existing APFS volume. In the sidebar, find your startup volume, typically named Macintosh HD, and select it. You want the volume itself, not the disk or container above it in the hierarchy.
- Add a new APFS volume. Go to Edit in the menu bar and choose “Add APFS Volume,” or click the add (+) button in the Disk Utility toolbar. Give the new volume a clear name such as “Golden Gate” so it is easy to identify at startup. Leave the format set to APFS. You do not need to reserve a fixed size unless you want a hard limit, because APFS volumes share the container’s free space dynamically. Click Add when you are ready.
- Download the macOS Golden Gate full installer. If you are enrolled in the developer program, download the full installer directly from developer.apple.com. You may also be able to access it via System Settings > General > Software Update by clicking the info button next to the beta. The download is approximately 17 GB, so give it time. You want the full installer application, not a delta update that would apply on top of your current volume.
Alternatively, you can download it using Terminal:
Go to Terminal on your Mac and copy and paste the below command and hit return:
softwareupdate --list-full-installersIt will bring up the list of macOS installers available to download from Apple. Copy and paste the below command in the Terminal and hit return to download macOS Golden Gate:
softwareupdate --fetch-full-installer --full-installer-version 27.0 - Launch the installer. Once the download finishes, the installer will open automatically, or you can find it in your Applications folder. On the first screen, click Continue and agree to the license terms.
- Click “Show All Disks.” The installer defaults to your current startup volume. On the installation destination screen, you must click “Show All Disks” to reveal the new APFS volume you created. Select the volume you named “Golden Gate,” not your existing Tahoe volume.
- Complete the installation. Click Continue and let the installer run. Your Mac will restart several times during the process. The first reboot will take noticeably longer than a standard startup, which is normal for a fresh OS install on the macOS 27 Golden Gate beta.
- Set up Golden Gate on the new volume. When the setup assistant appears, configure it as you would a new Mac, or sign in with your Apple ID. Your Tahoe volume is untouched and still on the same disk.
- Open Disk Utility. You can find it in Applications > Utilities or by searching with Spotlight. Make sure you are running this from your existing Tahoe installation.
Switching between macOS versions
To switch between Tahoe and Golden Gate, restart your Mac and hold the power button until you see the startup options screen. Both volumes will appear as selectable options. Click the one you want, then click Continue. You can also set a default startup volume in System Settings > General > Startup Disk, which is useful if you plan to spend most of your time in one OS and only occasionally boot into the other. Note that there are some known startup disk issues with dual-boot setups on certain Macs running the beta.
If you decide Golden Gate is not for you, removing it means booting back into Tahoe, opening Disk Utility, selecting the Golden Gate volume, and clicking the delete volume button. The space is immediately returned to your disk’s free pool, and your Tahoe volume and its data are unaffected.
macOS Golden Gate beta 2 is the latest developer release at the time of writing, with a public beta expected in July 2026 and the stable release targeted for September 2026.
