Many users with M1-based Macs are experiencing serious issues when trying to install or upgrade to macOS Sequoia 15.4. These include kernel panics, repeated reboots, “unable to downgrade” errors, and the message: “The version of macOS on the selected disk needs to be reinstalled.” This happens both with standard upgrades and clean installs. It appears to be a software bug introduced in macOS Sequoia 15.4, likely affecting Apple Silicon (M1/M2) systems due to low-level driver changes (e.g., AppleT8020DART).
Here is a working solution:
- Download the earlier version of macOS Sequoia 15.2 on another Mac.
- Open Terminal and run:
softwareupdate --fetch-full-installer --full-installer-version 15.2
- Create a bootable USB installer.
- Plug in a USB drive (at least 16 GB), open Disk Utility, and erase it using:
- Format: Mac OS Extended (Journaled)
- Scheme: GUID Partition Map
- Name: MyInstaller
- Then run in Terminal:
sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/MyInstaller
- Boot your M1/M2 Mac from the USB installer.
- Shut down the Mac.
- Press and hold the Power button until “Loading startup options” appears.
- Select the USB installer and click Continue.
- Erase the internal disk. This step is critical:
- In the macOS Utilities screen, open Disk Utility.
- Click “View” and choose “Show All Devices.”
- Select the top-level internal disk (e.g., “APPLE SSD”).
- Click Erase, and follow the prompts.
- On newer Macs, you’ll see a simplified prompt saying that all data on Macintosh HD will be erased and the Mac will restart.
- Confirm and proceed.
- Do not attempt to erase “macOS Base System” or any “macOS disk image” — these are part of the USB installer and should remain.
Important: This will permanently erase all user data on the Mac, including files, applications, and settings.
- Reinstall macOS Sequoia: After the Mac reboots, it will return to the macOS installer. Proceed with installing macOS Sequoia onto the newly erased disk.
- Once installed, your Mac should boot normally into Sequoia 15.2 without the issues seen in 15.4. Avoid upgrading to 15.4 until Apple releases a fix.
- If you already attempted to install 15.4 and are now stuck, you must erase the disk as described above. Simply trying to install an older version like 15.2 over a failed 15.4 install will usually result in errors such as “unable to downgrade."
Additional note:
Recovery Mode requires an internet connection to fully function. When entering a Wi-Fi password, your keyboard may default to a QWERTY layout, even if your usual layout is different. Changing the layout from the top-right language selector may not work, so you should type your Wi-Fi password as if using a QWERTY keyboard.