Apple Diagnostics
test your Mac

/ SprUng, TOOLS / 4 minutes of reading

Use Apple Diagnostics to test your Mac

Apple Diagnostics, formerly known as Apple Hardware Test, can check your Mac for hardware issues.

If you think your Mac might have a hardware issue, you can use Apple Diagnostics to help determine which hardware component might be at fault. Apple Diagnostics also suggests solutions and helps you contact Apple Support for assistance.

Prepare your Mac

  1. Shut down your Mac.
  2. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power.
  3. Make sure that your Mac is on a hard, flat, stable surface with good ventilation.

Start Apple Diagnostics

Determine whether you’re using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

  1. Turn on your Mac and continue to press and hold the power button as your Mac starts up.
  2. Release when you see the startup options window, which includes a gear icon labeled Options.
  3. Press Command (⌘)-D on your keyboard.

Intel processor

  1. Turn on your Mac, then immediately press and hold the D key on your keyboard as your Mac starts up.
  2. Release when you see a progress bar or you’re asked to choose a language.

View the test results

Apple Diagnostics shows a progress bar while it’s checking your Mac:

When testing is complete, Apple Diagnostics shows the results, including one or more reference codes. Learn about Apple Diagnostics reference codes.

Mac Diagnostic Codes

Apple Diagnostics reference codes

https://support.apple.com/en-us/HT203747

Get more information about the reference codes shown in Apple Diagnostics test results.

When you use Apple Diagnostics to test your Mac, the test results include one or more reference codes. If you can't use this information to resolve the issue, please contact Apple or take your Mac to an Apple Authorized Service Provider (AASP) or Apple Store for service or support. Provide the code you received from the test.

Code Definition More information
ADP000 No issues found No issues found.
ALS001 There may be an issue with the ambient light sensor. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
BMT001 BMT003 BMT004 BMT005 There may be an issue with the Touch ID sensor. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
CNW001 CNW003 CNW004 CNW005 CNW006 There may be an issue with the Wi-Fi hardware. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
CNW007 CNW008 No Wi-Fi networks are detected: No Wi-Fi networks are in range, or the Wi-Fi hardware might have an issue. Run the test again in range of a Wi-Fi network. If this code appears again, further troubleshooting may be required. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
DFR001 There may be an issue with the Touch Bar. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDC001 NDC003 NDC004 NDC005 NDC006 There may be an issue with the camera. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDD001 There may be an issue with the USB hardware. Disconnect all external devices except keyboard, mouse, and Ethernet adapter (if applicable). Run the test again. If this code appears again, further troubleshooting may be required. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDK001 NDK003 NDK004 There may be an issue with the keyboard. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDL001 There may be an issue with the Bluetooth hardware. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDR001 NDR003 NDR004 NDR005 NDR006 There may be an issue with the trackpad. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NDT001 NDT002 NDT003 NDT004 NDT005 NDT006 There may be an issue with the Thunderbolt hardware. Disconnect external Thunderbolt devices and run the test again. If this code appears again, further troubleshooting may be required. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
NNN001 A serial number was not detected. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PFM001 PFM002 PFM003 PFM004 PFM005 PFM006 PFM007 There may be an issue with the System Management Controller (SMC). Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PFR001 There may be an issue with the computer's firmware. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPF001 PPF003 PPF004 There may be an issue with the fan. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPM001 There may be an issue with a memory module. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPM002 PPM003 PPM004 PPM005 PPM006 PPM007 PPM008 PPM009 PPM010 PPM011 PPM012 PPM013 PPM014 PPM015 There may be an issue with the onboard memory. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPP001 PPP002 PPP003 There may be an issue with the power adapter. Disconnect the power adapter from the computer and wall outlet, then reconnect. Run the test again. If this code appears again, further troubleshooting may be required. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPP007 The power adapter was not tested. There may be an issue with the power adapter, or it may not be connected to the computer or wall outlet. Check the connections and run the test again. If this code appears again, contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPR001 There may be an issue with the processor. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT001 The battery was not detected. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT002 PPT003 The battery will need to be replaced soon. It is functioning normally, but holds less charge than it did when it was new. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT004 The battery requires service. The battery is not functioning normally, though you might not notice a change in its behavior or the amount of charge it holds. You can continue to use your battery before it’s checked without harming your computer. If you're using a Mac with an Intel processor, you can confirm this result by using Apple Diagnostics over the internet: Choose Shut Down from the Apple menu , then turn on your Mac again and immediately press and hold Option-D until Apple Diagnostics begins. ~~ ~~If this code appears again or you're using a Mac with Apple silicon, contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT005 The battery is not installed properly. Shut down and discontinue use. The computer requires service. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT006 The battery requires service. The battery is not functioning normally, though you may not notice a change in its behavior or the amount of charge it holds. You can continue to use your battery before it’s checked without harming your computer. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
PPT007 The battery needs to be replaced. The battery is functioning normally but holds significantly less charge than it did when it was new. You can continue to use the battery until you replace it, without harming your computer. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VDC001 VDC003 VDC004 VDC005 VDC006 VDC007 There may be an issue with the SD card reader. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VDH002 VDH004 There may be an issue with a storage device. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VDH005 Unable to start macOS Recovery. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VFD001 VFD002 VFD003 VFD004 VFD005 VFD007 There may be an issue with the display. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VFD006 There may be an issue with the graphics processor. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.
VFF001 VFF002 VFF003 There may be an issue with the audio hardware. Contact Apple or take your computer to an AASP or Apple Store to learn which service and support options are available.

Published Date: November 17, 2020

To repeat the test, click “Run the test again” or press Command-R.

To restart your Mac, click Restart or press R.

To shut down, click Shut Down or press S.

To get information about your service and support options, make sure that your Mac is connected to the internet, then click ”Get started” or press Command-G. Your Mac will restart to a webpage with more information. When you’re done, choose Restart or Shut Down from the Apple menu.

Learn more

On an Intel-based Mac, if you can’t start Apple Diagnostics with the D key, try these solutions:

  • Press and hold Option-D at startup to use Apple Diagnostics over the internet.
  • Make sure that your Mac isn’t using a firmware password.

Root User – Mac

https://support.apple.com/en-us/HT204012

How to enable the root user on your Mac or change your root password

Mac administrators can use the root user account to perform tasks that require access to more areas of the system.

The user account named ”root” is a superuser with read and write privileges to more areas of the system, including files in other macOS user accounts. The root user is disabled by default. If you can log in to your Mac with an administrator account, you can enable the root user, then log in as the root user to complete your task.

The root user account is not intended for routine use. Its privileges allow changes to files that are required by your Mac. To undo such changes, you might need to reinstall your system software. You should disable the root user after completing your task.

It’s safer to use the sudo command in Terminal instead of enabling the root user. To learn about sudo, open the Terminal app and enter man sudo.

Enable or disable the root user

  • Choose Apple menu () > System Preferences, then click Users & Groups (or Accounts).
  • Click lock icon, then enter an administrator name and password.
  • Click Login Options.
  • Click Join (or Edit).
  • Click Open Directory Utility.
  • Click lock icon in the Directory Utility window, then enter an administrator name and password.
  • From the menu bar in Directory Utility:
    • Choose Edit > Enable Root User, then enter the password that you want to use for the root user.
    • Or choose Edit > Disable Root User.

Log in as the root user

When the root user is enabled, you have the privileges of the root user only while logged in as the root user.

  • Choose Apple menu > Log Out to log out of your current user account.
    At the login window, log in with the user name ”root” and the password you created for the root user.

  • If the login window is a list of users, click Other, then log in.
  • Remember to disable the root user after completing your task.

Change the root password

  1. Choose Apple menu () > System Preferences, then click Users & Groups (or Accounts).
  2. Click lock icon, then enter an administrator name and password.
  3. Click Login Options.
  4. Click Join (or Edit).
  5. Click Open Directory Utility.
  6. Click lock icon in the Directory Utility window, then enter an administrator name and password.
  7. From the menu bar in Directory Utility, choose Edit > Change Root Password…
  8. Enter a root password when prompted.
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