Users on the Apple Support Community report macOS Tahoe installation failure on the M3 Ultra Mac Studio that was released earlier this year.
macOS Tahoe 26 was released earlier this week and downloads successfully. But the installation fails and the system reverts to macOS Sequoia 15 when the system restarts. The problem may be tied to the Sequoia update Apple released on the same day as macOS Tahoe 26.
The problematic Mac Studio systems that can’t install Tahoe had Sequoia 15.7 installed before Tahoe.
It is unlikely there was wide testing done of the update from macOS 15.7 to macOS 26. This might explain why the macOS Tahoe installation failure wasn’t picked up earlier.
Apple Support is on the case
The discussion thread in the Apple Support Community notes that Apple Support in Europe is aware of the issue and is investigating. Older Mac Studio systems, running M1 and M2 system chips, have not encountered any issues. The issue seems to be with a specific driver that is needed for the update that is missing in macOS 15.7.
My M2 Max Mac Studio upgraded without incident. The M3-powered MacBook Air I use had no hassles through the entire sequence of developer beta versions. But every system has a different combination of hardware and applications so your mileage may vary.
Ensure you have a reliable back up before installing a new operating system or making any significant changes to your system, A cloning tool like SuperDuper or Carbon Copy Cloner that creates a complete duplicate of your system is a great fail safe.
Anthony is the founder of Australian Apple News. He is a long-time Apple user and former editor of Australian Macworld. He has contributed to many technology magazines and newspapers as well as appearing regularly on radio and occasionally on TV.