Updated September 29, 2025: Apple released the macOS Tahoe 26.0.1 update. According to the release notes, “This update provides important bug fixes, security updates, and resolves an issue that prevented some users from upgrading to macOS Tahoe on Mac Studio (M3 Ultra, 2025).” The article below was originally posted on September 17, 2025.
When Apple releases major updates to its operating systems, we here at Macworld usually advise people to hold off for a few days before installing, just in case. Though this time, following the release of macOS Tahoe last Monday, we didn’t feel as cautious as we did in the past, because the betas have been really stable. But it looks like we should’ve heeded our old advice.
The Apple Support Community has a thread about the M3 Ultra Mac Studio and users who can’t install macOS Tahoe. In many instances, users run the installation and everything seems to move along nicely, but when the Mac reboots (which is required when updating macOS), the system launches into macOS Sequoia, not Tahoe.
Ken Gruberman, who writes The Tech Daddy Substack, encountered this problem when attempting to install Tahoe on his own M3 Ultra Mac Studio. He told me via email that he spent the “better part” of a day trying to do the installation in the internal SSD, as well as on an external drive.
Gruberman and the Apple Support postings point out that the problematic Mac Studios had Sequoia 15.7 installed; Sequoia 15.7 was released on Monday, along with Tahoe. It seems that during the installation, Tahoe is looking for a driver but fails to find it, resulting in a failed installation. Other posts in the thread state that other ways of performing an installation (such as in Safe Mode or with an installer on an external USB drive) also failed.
A post in the thread states that Apple Support Europe is aware of the problem and is working on a fix. Apple PR was contacted for comment and did not respond at the time of this posting.
If the issue is indeed tied to the Sequoia 15.7 update, that could explain how it was not caught before both updates were released. Apple often follows up major releases with point updates to fix these issues. M3 Ultra Mac Studio owners who updated to Sequoia 15.7 and haven’t updated to Tahoe yet should wait until such an update is available. Users who attempted to do the installation but failed can take some solace in that the Mac reverts to Sequoia and is still usable.
