You install a macOS update. The Mac restarts, shows the Apple logo and a progress bar, and the bar moves for a while. Then it stops. Ten minutes pass, then thirty, and nothing changes.

The most important thing to know: a stalled progress bar is usually not a stuck Mac. The worst thing you can do is force it off too early. Here’s how to tell the difference between working and stuck, and what to do, in order, if it really is stuck.

Why the bar stops moving

The progress bar during an update is an estimate, not a live measurement. Some stages move it steadily; others, such as preparing the system volume, updating firmware and migrating settings, can take a long time without moving it at all. The screen may also go black, show the Apple logo again, or restart several times. All of that is normal.

Updates take longest on Macs that are low on free space, on older or slower drives, after skipping several versions, and on the first boot of a major release.

How long to wait

  • Connect power. If it’s a MacBook, plug it in now and leave it plugged in. A laptop that runs out of battery mid-update is a much bigger problem than a slow one.
  • Wait at least an hour from the moment the bar stopped, and ideally two, before intervening. Don’t close the lid.
  • Look for signs of life. A bar that moves even slightly, the screen going black and coming back, or a restart are all signs that it is still working.

If nothing at all has changed after two hours, it is reasonable to treat it as stuck.

Step 1: Force a restart

Press and hold the power button (Touch ID on laptops) for about 10 seconds until the Mac turns off. Wait a few seconds, then press it again to turn it on.

In many cases, the update simply resumes, or the Mac boots normally into the new version. If it returns to the same stalled bar, give it another 30 minutes before moving on.

Before you try again, unplug everything except power: docks, hubs, external drives, displays and USB accessories. A misbehaving accessory can stop a Mac from finishing its startup.

Step 2: Try Safe Mode

Safe Mode starts the Mac with only essential software and runs a basic disk check. If the Mac starts in Safe Mode, a third-party extension or login item is usually what’s blocking normal startup.

  • Apple silicon: shut down. Press and hold the power button until you see Loading startup options. Select your startup disk, hold Shift, and click Continue in Safe Mode.
  • Intel: turn on or restart the Mac and immediately hold Shift until the login window appears.

If Safe Mode works, restart normally. If the normal start still fails, remove recently installed utilities, especially antivirus, VPN, system-tweaking or menu bar apps, from Safe Mode and try again.

Step 3: Run Disk Utility from Recovery

If the Mac won’t start even in Safe Mode, start it in macOS Recovery:

  • Apple silicon: shut down, then press and hold the power button until you see Loading startup options. Click Options, then Continue.
  • Intel: turn it on and immediately hold Command-R until you see the Apple logo.

Open Disk Utility, choose View > Show All Devices, select your internal disk and each volume on it in turn, and click First Aid. Then restart.

Step 4: Reinstall macOS over the top

If First Aid finds nothing and the Mac still won’t start, go back to Recovery and choose Reinstall macOS. This replaces the system but keeps your apps, files and settings. It downloads the installer, so connect to Wi-Fi first, and expect it to take a while.

Choose your existing startup disk when asked. Don’t use Disk Utility to erase anything at this stage unless you have a current backup and have decided to start over.

Step 5: Revive an Apple silicon Mac

If an Apple silicon Mac won’t even reach Recovery, its firmware may be damaged. Apple provides a revive process that reinstalls the firmware and recoveryOS without erasing your data. It needs a second Mac running Apple Configurator, or a recent version of Finder, and a USB-C cable. Apple’s support guide on reviving or restoring a Mac with Apple silicon walks through the key combination for each model.

Choose Revive, not Restore. Restore erases the Mac.

When to get help

If a revive fails, or the Mac shows no signs of life at all, book an appointment with Apple or an authorised service provider. Mention the update that was being installed. If you don’t have a backup, say so before they start; the first thing a repair desk may do is erase the drive.

Before the next update

  • Back up with Time Machine first.
  • Keep at least 30 to 40 GB free. Our guide to how much space an update really needs explains why.
  • Plug laptops in and unplug docks and drives before you click Update.
  • Start big updates in the evening, when you can leave the Mac alone.

The short version

A progress bar that stops during a macOS update is usually still working. Plug in, wait one to two hours, then force a restart with everything unplugged. If it still won’t start, try Safe Mode, then Disk Utility First Aid in Recovery, then Reinstall macOS, which keeps your data. For an Apple silicon Mac that won’t reach Recovery, a revive from another Mac repairs firmware without erasing anything.