Problem Booting Into macOS Operating System

Summary

Troubleshooting steps for a macOS computer not booting.

Body

Issue/Question

Computer is getting the progress bar that gets to about 50%, the screen then goes white and restarts

Computer is blinking an image of a folder with a question mark in it

Environment

  • macOS

Cause

Unknown cause

Resolution

  1. Select the correct boot device
    1. Turn off the computer
    2. Turn the computer back on
    3. Immediately press and hold Option
    4. Click the arrow beneath the drive labeled Macintosh HD
  2. Try PRAM reset
    1. Turn off the computer.
    2. Turn the computer back on
    3. Immediately press and hold COMMAND+OPTION+P+R keys
    4. System will chime and restart
    5. Release the keys
  3. Try booting to Safe Boot.
    1. Turn off the computer
    2. Turn the computer back on
    3. Immediately press and hold the SHIFT key until system boots
  4. Try First Aid Repair
    1. Turn system off
    2. Turn system on
    3. Hold Option+R
    4. System should boot to Recovery
    5. Open Disk Utility from the macOS Utilities window
    6. Select your startup disk from the left side of the window
      Note: This is usually named Macintosh HD
    7. Click the First Aid tab
    8. Click the Repair Disk button to verify and repair any issues with your startup disk
    9. After your disk is successfully repaired, quit Disk Utility and restart your Mac
  5. Try booting to Internet Recovery mode
    1. Plug the computer into a working Ethernet port
    2. Turn off the computer
    3. Turn the computer back on
    4. Immediately press and hold the COMMAND+OPTION+R keys until the system boots
    5. Run Disk Utility

Details

Details

Article ID: 29
Created
Wed 6/6/18 3:33 PM
Modified
Fri 2/7/20 2:40 PM
KCS Article Status
WIP: Only Problem & some Environment captured
Not Validated: Complete & Resolution captured, confidence lacks in structure, content, no feedback
Validated: Complete & reusable, used by licensed KCS user, confidence in resolution & std. compliance
Validated