macOS 27.0.1 (Golden Gate)
The First Bug-Fix Update to macOS 27 — Superseded by macOS 27.2
What's in macOS 27.0.1
Apple released macOS 27.0.1 (build 26A434) on September 28, 2026, two weeks after macOS 27 Golden Gate shipped. Apple's release notes say only that it “fixes bugs”; the enterprise notes add a single named fix for Platform SSO sign-in. The download is roughly 3.3 GB, and Apple's security page lists no CVE entries for this update.
It arrived alongside two security updates for older Macs, macOS Tahoe 26.7.1 and macOS Sequoia 15.8.1, which patched a CoreGraphics flaw Apple says may have been exploited in a targeted attack. If you were on Tahoe at the time, that was the more urgent install.
Superseded by macOS 27.2
macOS 27.0.1 was the only 27.0.x release. Apple skipped 27.1 and shipped macOS 27.2 (build 26B123) on October 26, 2026, which includes everything in 27.0.1 plus new Siri AI languages and a large batch of security fixes. If Software Update offers you 27.2, install that instead.
Why Was There No macOS 27.1?
Apple's first 27.x developer beta, seeded on September 16, was labelled 27.2 from day one. The best explanation reported so far is that the 27.1 number was reserved for an iOS 27.1 build that shipped only on the iPhone Duo, and Apple kept the version numbers aligned across platforms. The practical result is a gap in the sequence, not a missing update: nothing was pulled.
How to Install
Open System Settings → General → Software Update. Macs already on 27.0.1 will see 27.2 instead. Back up first, keep the Mac plugged in, and expect one restart. Our macOS update guide covers the details.