Troubleshoot Mac Startup Issues

General Information

Important Terms

  • Safe Mode – A way to start up your Mac so that it performs certain checks and prevents some software from automatically loading or opening.

Reset System Management Controller (SMC)

Resetting the SMC can resolve a variety of issues, including (but not limited to):

  • Mac not powering on when pressing the power button or opening the laptop
  • Battery or status lights behaving strangely
  • Trackpad not working
  • Not connecting to Wi-Fi
  • Internal fans running high during low CPU load
  1. If the Mac is on, shut it down by holding the Power button.
  2. Unplug the power cord from the back of the Mac.
  3. Wait at least 15-seconds.
  4. Reconnect the power cord.
  5. Turn on the Mac.
  1. If the Mac is on, shut it down by holding the Power button.
  2. On the left side of the keyboard, press and hold the Shift, Control, and Option keys.
  3. While holding the previous keys down, also hold down the Power button.
  4. Hold all keys for 10 seconds.
  5. Release the keys.
  6. Turn on the Mac.
  1. If the Mac is on, shut it down by holding the Power button.
  2. Remove the battery.
  3. Press and hold the Power button for 5 seconds.
  4. Reconnect the battery.
  5. Turn on the Mac.

Apple Silicon (M1) Macs do not have a system management controller and cannot be reset.

Boot into Safe Mode

  1. Make sure the Mac is completely shut down.
  2. Press the power button and immediately hold down the Shift key.
  3. Continue to hold the Shift key until the Apple logo appears. The Mac will take longer than normal to boot as it performs some maintenance tasks.
  4. Go to Apple > Restart. This will reboot the computer in normal mode.

If the computer boots normally, the issue has been resolved.

Run First Aid

Boot into Internet Recovery

  1. Make sure the Mac is completely shut down.
  2. Press the power button and then immediately hold down Command+Option+R keys until a spinning globe icon appears.

If the globe icon does not appear, the most likely cause is that the key combination was either not pressed quickly enough, or was released too soon. You can shut the machine down by holding the power button for at least 10-seconds and retrying the steps above.

Run First Aid

  1. Click Disk Utility.
  2. Click Continue.
  3. Click View button.
  4. Select Show All Devices.
  5. On the left, under the Internal section, select the top-most selectable item.
  6. On the toolbar, click First Aid.
  7. Click Run. Disk Utility will attempt to repair any errors. If any errors were found and/or repaired, re-run First Aid at least one more time.
  8. Go to Apple > Restart.

If the computer boots correctly, the issue has been resolved.

Reinstall macOS

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Boot into Internet Recovery

  1. Make sure the Mac is completely shut down.
  2. Press the power button and then immediately hold down Command+Option+R keys until a spinning globe icon appears.

If the globe icon does not appear, the most likely cause is that the key combination was either not pressed quickly enough, or was released too soon. You can shut the machine down by holding the power button for at least 10-seconds and retrying the steps above.

Reinstall Mac Operating System

This process will install macOS over top of the current installation and user data will remain intact,

  1. Click Reinstall macOS.
  2. Click Continue.
  3. Click Continue.
  4. Click Agree.
  5. Click Agree.
  6. Select the Macintosh HD icon.
  7. Click Install. The Operating System will begin to install and the computer may reboot several times.

If the computer boots correctly, the issue has been resolved.

Wipe and Reinstall macOS

Note: This is a destructive troubleshooting method. All files will be deleted.

For directions, see the Wipe and Reinstall macOS article.