macOS 27 has broken boot drive selection for some
appleinsider.com Jun 10, 2026

macOS 27 has broken boot drive selection for some

AI-summarised brief · reviewed before publication

A bug in macOS 27 is preventing users from selecting alternate partitions or drives to boot from, affecting Asahi Linux users who rely on multiple operating systems on their Mac. The issue is caused by a change in how the boot picker and Startup Disk applications detect valid OS boot volumes. Users who have updated to macOS 27 can restore access to their Asahi Linux partition by setting macOS 26 as the default Startup Disk. The Asahi team will not support users who have installed the macOS 27 beta without making contingency plans.

💡 Why It Matters

  • · This issue highlights the risks of installing developer betas, which can introduce bugs and malfunctions that may not be fixed until the final release.
  • · Mainstream Mac users should wait for the final fall release or the usual public beta track to avoid potential problems.