Everything here is general guidance, not professional advice. We research carefully and can still be wrong or out of date, so treat it as suggestions to check rather than instructions to follow, and accept that you act on it at your own risk. Full terms.

Disaster Lab
PlaybooksComputer will not start after an update
Infrastructuredisruptive25 minutes to prepare

Computer will not start after an update

A Windows or macOS update leaves the computer stuck, restarting, or unable to reach the desktop.

01DetectConfirm the signal
02ContainStop more damage
03RecoverRestore control
04VerifyProve it works

What do you need right now?

Prepare before it happensRecover from this now

Your preparation

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What this means

An update can take much longer than an ordinary restart. A progress bar that pauses is not proof that the computer is broken.

The dangerous moment is when impatience turns a slow update into an interrupted one. Keep the computer powered, wait, and use recovery tools before choosing anything that erases files.

Recovery may ask for a FileVault or BitLocker recovery key. That key needs to exist somewhere other than the computer that will not start.

Warning signs

  • The update reports too little free storage before restarting.
  • The computer loops through the same restart or error screen.
  • A progress bar remains unchanged for several hours.
  • Windows opens Automatic Repair, or the Mac shows a question mark or blank screen.
  • Recovery asks for an encryption key you have never saved elsewhere.

Recover now

First 15 minutes

  1. Connect reliable power and wait. Give a major update at least an hour before forcing it off. Apple notes that installation progress can pause for long periods.
  2. Photograph the screen and error code. Record what the computer was installing and when the last visible change happened.
  3. Disconnect non-essential accessories. Remove docks, printers, external drives, and USB devices, but keep power and a wired keyboard or mouse if needed.
  4. Try one normal restart. Hold the power control only if the computer has clearly stopped responding. Repeated forced shutdowns can make disk damage worse.
  5. Open the recovery tools for your platform. Start with repair options that preserve files.

Use the built-in recovery tools

  1. Turn the Mac off. On Apple silicon, hold the power button until startup options appear, then choose Options → Continue. On an Intel Mac, start it while holding Command-R.
  2. In macOS Recovery, open Disk Utility, select the startup disk, and run First Aid. Restart once when it finishes.
  3. If the Mac still does not start, return to Recovery and choose Reinstall macOS. Reinstalling without erasing normally keeps personal files, but a backup is still safer.
  4. If Recovery does not open or a firmware symbol appears, stop and use Apple Support. Some Apple-silicon and T2 Macs need a firmware revive from another Mac.
  1. Let Windows enter the Windows Recovery Environment after repeated failed starts. You can also start from a recovery USB drive.
  2. Choose Troubleshoot → Advanced options → Startup Repair first.
  3. If the failure began with an update, choose Uninstall Updates and remove the latest quality update before considering the larger feature update.
  4. If needed, try System Restore or Startup Settings → Safe Mode. These preserve more than a reset or reinstall.
  5. Stop before Reset this PC or reinstalling Windows unless your files are backed up and you understand which apps and data will be removed. Some recovery tools require the BitLocker key.

Today

  1. If the computer starts, back up important files before retrying the update.
  2. Check free storage and remove only files you recognize. Keep at least enough room for the update and its temporary files.
  3. Install pending app, driver, and firmware updates from the computer or hardware manufacturer.
  4. Run the update again on reliable power and internet, without unnecessary accessories attached.
  5. If recovery cannot see the startup disk, reports hardware errors, or asks to erase the only copy of important files, stop and get qualified repair or data-recovery help.

Verify recovery

  • The computer reaches the desktop twice after normal restarts.
  • Disk repair or startup repair reports no remaining error.
  • Important files open and a fresh backup completes.
  • The installed operating-system version is supported and receives security updates.
  • The FileVault or BitLocker recovery key is available from another device.

Prepare now

Before an update

  • Automatic backup is current, and one file has been restored as a test.
  • At least 20 GB or the manufacturer’s stated requirement is free before a major upgrade.
  • The FileVault or BitLocker recovery key is stored in a password manager or printed record away from the computer.
  • Major upgrades happen when the computer can remain on power and unused for several hours.

Recovery access

  • You know whether the Mac has Apple silicon or an Intel processor, because the Recovery startup steps differ.
  • The Apple Account and FileVault recovery details are accessible from another device.
  • Time Machine shows a recent completed backup.
  • A Windows recovery drive exists on a labelled USB drive and is recreated after major system changes.
  • The BitLocker recovery key is visible from another device or printed.
  • File History or Windows Backup shows a recent completed backup; a recovery drive does not contain personal files.

Common mistakes

  • Forcing the computer off as soon as progress pauses. Updates can sit at one point for a long time while still working.
  • Choosing erase, reset, or reinstall first. Startup repair, disk repair, update removal, and safe mode preserve more.
  • Discovering the recovery key is on the broken computer. Encryption works against its owner too when the key is unavailable.
  • Using a recovery USB as the file backup. Windows recovery media contains system files, not your documents and photos.
  • Retrying with a nearly full disk. Updates need working room in addition to the final installed size.

Sources

Last reviewed July 27, 2026Guidance changes. Confirm provider-specific actions in the linked official sources.