Won't bootCriticalMac won’t start up
What this error means
This means your Mac is not getting past startup and may stop at a blank screen, Apple logo, progress bar, or login screen. It can happen after a macOS update, a power problem, a disk issue, or when a startup app or accessory is blocking boot.
Common causes
- 1Power is interrupted or the battery is too low to start normally
- 2macOS system files or startup data are damaged
- 3The startup disk has a file system problem or is nearly full
- 4A connected accessory, peripheral, or external drive is preventing startup
How to fix it
- Unplug all accessories. Shut down the Mac if possible, then disconnect printers, external drives, hubs, and other peripherals. Leave only power connected, then try starting up again.
- Force a full restart. Press and hold the power button until the Mac turns off. Wait 10 seconds, then press the power button again. If you use a MacBook, make sure it is plugged into power for at least 15 minutes before trying again.
- Start in Safe Mode. Safe Mode can help the Mac load with fewer background items and can reveal whether a startup app is causing the problem. If the Mac starts in Safe Mode, restart normally afterward and check whether it boots on its own.
- Check the startup disk with Disk Utility. If you can reach macOS Recovery, open Disk Utility and run First Aid on the startup disk. This checks for common disk problems that can block startup.
- Make sure there is enough free storage. If the Mac does start in Safe Mode or Recovery and you can open the disk, remove large unused files if storage is nearly full. A nearly full disk can stop macOS from finishing startup.
- Install any available macOS updates. Once the Mac boots successfully, install the latest updates from System Settings to fix startup bugs and improve disk and system stability.
- If it still will not boot, get support. A failing drive, logic board issue, or deeper system damage may need repair. Avoid repeated forced shutdowns if the Mac is making unusual sounds, gets very hot, or keeps restarting.
Recommended fixes
Restart your device
A restart clears temporary state that often causes transient errors.
- Save your work and close open apps.
- Restart the device from the power menu.
- Reproduce the issue to check whether it persists.
Install macOS updates
- Open System Settings > General > Software Update.
- Install any available updates.
- Restart if prompted.
Boot into Safe Mode (Mac)
Apple silicon: shut down, hold the power button until startup options appear, select your startup disk, then hold Shift and choose Continue in Safe Mode.
Intel: restart and hold Shift until the login window appears.
Run First Aid in Disk Utility (Mac)
- Open Disk Utility.
- Select your startup disk and click First Aid.
- Let it verify and repair the disk.
Contact Quickfix support
If the issue persists after trying these steps, reach out so we can help.
Visit the contact page and include your scan report code.
When to seek help
Seek professional help right away if your Mac shows a folder with a question mark, repeats a restart loop, makes clicking or grinding noises, smells hot or burnt, or still will not start after Safe Mode and disk repair. You should also get help if you need the data on the Mac and have not been able to back it up, because continued attempts can make data recovery harder.
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