Mac

macOS update stuck or won't finish installing

A macOS update that hangs on the progress bar or restarts repeatedly is usually a large download continuing in the background, low disk space, or a corrupted installer file.

Difficulty
Moderate
Time
1–4 hours
DIY cost
$0
Pro cost
$100–$200

Symptoms

  • Progress bar stays at the same percentage for a very long time
  • Update seems to restart the installation process repeatedly
  • Available storage was low before starting the update
  • Update was interrupted by a restart, sleep, or power loss

Likely causes

  • CommonA large update genuinely taking a long time on an older MacSome stages, especially near certain percentages, can look stalled while still working.
  • CommonNot enough free disk space to complete the installmacOS needs substantial free space to stage and apply an update.
  • PossibleA corrupted or incomplete update downloadAn interrupted download can cause the installer to fail or hang.
  • PossibleAn unstable internet connection during downloadThis can cause the update file itself to be incomplete.
  • Less commonA conflicting third-party security or system-level toolSome deep system software can interfere with the update process.

What to do

  1. Let the progress bar sit for at least an hour before assuming it's truly stuck; some stages are just slow.
  2. Make sure the Mac stays plugged into power and doesn't go to sleep during the update.
  3. If it's been stuck for many hours with no fan activity or disk light change, force a restart by holding the power button for 10 seconds.
  4. After restarting, check if macOS resumes the update automatically or returns to the desktop.
  5. Check available storage in About This Mac > Storage; free up space if it's low before retrying.
  6. Retry the update from System Settings > General > Software Update, ideally on a stable Wi-Fi connection.
  7. If it fails again, restart into Safe Mode (or Recovery Mode on Apple silicon) and try installing from there.
  8. As a last resort, use macOS Recovery to reinstall macOS, which typically preserves your files but you should back up first.

Tools and parts

  • None required

When to call a pro

If the update repeatedly fails or the Mac won't boot afterward, an Apple Store or authorized repair shop can safely reinstall macOS without data loss.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.