macOS update won't install: unstick a stalled upgrade

Steps

1. 01

   Wait before you call it stuck

   • Apple says the Apple logo or progress bar can stay far longer than usual during an install, and can pause for long stretches without moving
   • Give it hours, not minutes — overnight if you can; that is why Apple suggests starting a big update in the evening
   • Only once it has genuinely stopped: press and hold the power button for up to 10 seconds until the Mac turns off, then press it again

   !Careful: Forcing the Mac off mid-install is a last resort, not a first move — an interrupted install is how a stalled update turns into a Mac that won't start.

2. 02

   Clear the two things that stall most installs

   • Free space: macOS Ventura or later,Apple menu›System Settings›General›Storage(Monterey and earlier:Apple menu›About This Mac›Storage tab) — a major installer needs tens of gigabytes temporarily
   • Connection: the installer keeps downloading macOS and fetching firmware details for your exact model, so it needs the internet throughout, not just at the start
   • Keep a laptop on its power adapter for the whole install

   Also see: Free up disk space with Storage Management

3. 03

   Back up before you retry

   • Run a Time Machine backup now, while the Mac still starts normally

   Why?

   Everything below repairs or reinstalls the system volume. A current backup is what keeps a failed retry an inconvenience rather than a disaster.

   Also see: Set up Time Machine properly

4. 04

   Retry the update from safe mode

   • Apple silicon:Apple menu›Shut Down, wait for it to power off, then press and hold the power button until 'Loading startup options' appears, select your volume, hold Shift and click 'Continue in Safe Mode'
   • Intel: turn on or restart the Mac and immediately hold Shift until the login window appears — you may have to log in twice
   • Then run the update again:Apple menu›System Settings›General›Software Update(Monterey and earlier:Apple menu›System Preferences›Software Update)

   ✓You should see: 'Safe Boot' appears in the menu bar. Safe mode keeps third-party software from loading at startup, which is what Apple suggests when the Software Update route keeps failing.

5. 05

   Still failing? Install from macOS Recovery

   • Apple silicon: press and hold the power button until 'Loading startup options' appears,then click Options›Continue
   • Intel: press the power button and immediately hold Command (⌘) and R until an Apple logo or spinning globe appears
   • In the utilities window, run Disk Utility → First Aid on your startup disk, quit Disk Utility, then choose 'Reinstall macOS'
   • If the installer asks which disk to use and offers both 'Macintosh HD' and 'Macintosh HD - Data', choose Macintosh HD
   • Let it finish without interruption — don't put the Mac to sleep and don't close the lid until the install completes
   • If an installer you downloaded earlier was reported as damaged, delete it and download it again once the disk is repaired

   Why?

   Recovery installs with nothing else running, which is why Apple recommends it when a normal update won't complete. Apple states that reinstalling macOS this way doesn't remove your apps or personal data — have a current backup anyway.