A fairly common issue that numerous MacBook users have reported is encountering “the disk Macintosh HD can’t be unlocked” error message. Typically, this message will appear during start up following a routine macOS update, rendering your MacBook unusable. Fortunately, there are five proven fixes that you easily attempt right away.
The disk Macintosh HD can’t be unlocked message indicates there is a redundant disk volume. To fix it, first launch macOS Recovery and run Disk Utility to repair disk errors. If the issue persists, erase redundant disk volumes, and reinstall macOS. As a final measure, reset the RVRAM and SMC.
That’s it! Your MacBook should start up and function properly again.
Interestingly this error has been most commonly reported after Mac users upgraded to Big Sur and Catalina.
There are five easy troubleshooting steps you can follow. Notably, these steps will work regardless of whether you have a MacBook Pro or MacBook Air. I recommend you follow these steps in the exact order outlined below.
Step 1: Run Disk Utility To Repair Disk Errors
The very first thing to do is run the Disk Utility to repair the startup disk.
Mac Disk errors may be responsible for introducing bugs within the operating system. The Mac Disk Utility is specifically designed to locate and fix these errors, which may in turn fix the issue.
If your Mac is able to start up, you can locate the Disk Utility by opening the Applications folder and then clicking Utilities.
Folks who encounter the error straight away during start up will need to use the macOS Recovery process.
The utilities in macOS Recovery can help you restore and reinstall macOS, repair hard disk issues, regain access if your Macbook account is locked, and more.
How To Open Disk Utility From macOS Recovery
- First, turn off your Mac by pressing and holding down the power button for 10 seconds.
- Next, while holding down Command and R, press the power button to turn on your Mac. You will now enter macOS Recovery.
- Finally, select Disk Utility from the pop up window and click Continue.
The Disk Utility window will now appear. Before you get started, click the Menu icon at the top and select Show All Devices from the drop down.
From the Disk Utility side bar, you will now be able to see each of your Mac disks.
The objective now, is under each disk to first repair volumes, then containers, and then the disk itself.
The order here matters! So again, volumes FIRST, then containers, and then the disk itself.
To do so, for the disk you are attempting to repair, simply click the last volume shown under the disk and then click First Aid and select Run.
Once the repair is complete, simply keep moving up the list and repeat this process until you have run a First Aid check on all available volumes and containers.
Lastly, run the First Aid check on the disk.
When you are all done, exit the Disk Utility and restart your Mac. The issue should be resolved!
Step 2: Erase Redundant Disk Volumes
Did your Disk Utility discover no errors or did it discover an error it could not repair? Or perhaps it repaired them all but the error reappears after restart? If this is the case, you will need to erase any redundant disk volumes.
IMPORTANT NOTE: Before proceeding, make sure you fully backup your MacBook data.
Once you have fully backed up your data, head back to Disk Utility vis macOS recovery. This time, take a closer look at the Disk Utility side bar.
Under normal MacBook conditions, you should observe a volume called “Macintosh HD” and a volume named “Macintosh HD – Data“.
However, following a macOS update (namely Big Sur and Catalina) users have reported observing redundant disk volumes.
The volumes may have different naming conventions but most often you will see two “Macintosh HD – Data” volumes. In some cases you may see a “Macintosh HD – Data – Data” volume.
One quick and easy way to confirm that the volumes are duplicates is to click on each of them and compare the used storage GB amount. If they are identical, then you have a redundant disk volume and this is the source of the issue.
To fix it, select the volume you want to delete from the sidebar and then click the Erase icon in the menu at the top of the window.
Step 3: Reinstall macOS
Once you have erased redundant volumes, it is time to reinstall macOS on your MacBook.
To reinstall macOS, you will need to once again enter macOS Recovery by holding down Command and R, while simultaneously pressing the power button to turn on your Mac.
Then, simply select Reinstall macOS from the pop up window, click Continue, and follow the on screen instructions.
If Command and R do not successfully initiate macOS Recovery, you can also try simultaneously holding down Shift, Option, Command, and R as well as just Option, Command, and R during startup.
In the rare event that none of these shortcuts work, you will need to use an external thumb drive as a startup disk to install a new macOS.
Step 4: Reset NVRAM and PRAM
In addition to repairing disk errors, erasing redundant disk volumes, and reinstalling macOS, there are two types of MacBook resets you can attempt.
Nonvolatile random-access memory (NVRAM) is an area where a very small amount of memory is stored on the MacBook for quick access. Parameter RAM (PRAM) is very similar and stores similar types of information.
Resetting your MacBook’s NVRAM and PRAM can solve the issue in many cases.
Fortunately, the process for resetting these are the same:
- First, power off your Mac.
- Then, power your Mac on and immediately hold down Command, Option, P and R all together for 20 seconds.
You can release the keys once you here the Mac startup sound or once the Apple logo appears and disappears for the second time.
Notably, if you have a firmware password set this reset process will not work.
You will need to first remove the password and then try again.
Step 5: Reset System Management Controller (SMC)
The other kind of reset you can try is a system management controller (SMC) reset.
Notably, the SMC dictates how your MacBook manages power. Resetting the SMC, can solve all sorts of Mac issues including the can’t unlock disk Mac message error.
Prior to attempting to reset your SMC, follow the steps below.
- First, shut down the MacBook.
- Next, press and hold down the power button for 10 seconds and then release it.
- After a few seconds, press the power button to turn your Mac on.
If the issue persists, you can move forward with the SMC reset procedure.
The process for how you reset the SMC on your MacBook varies depending on whether or not you have a T2 chip and the battery location.
How To Reset SMC – MacBooks With T2 Chip
- First, power off your MacBook.
- Then, press and hold the Control, Option and Shift keys at the same time for 7 seconds.
- Next, while still holding these three keys, press and hold the power button as well for an additional 7 seconds. After the 7 seconds, release all four keys.
- Finally, wait 3 to 5 seconds and then press the power button once and release to turn on the MacBook.
How To Reset SMC – MacBooks Without T2 Chip & Non-removable Battery
- First, power off your MacBook.
- Then, press and hold the Control, Option and Shift keys at the same time.
- Next, while still holding these three keys, press and hold the power button as well. After 10 seconds, release all four keys.
- Finally, wait 3 to 5 seconds and then press the power button once and release to turn on the MacBook.
How To Reset SMC – MacBooks Without T2 Chip & Removable Battery
- First, power off your MacBook.
- Next, fully remove the battery.
- Then, press and hold down the power button for 5 seconds and then release it.
- Reinsert the battery.
- Finally, press the power button to turn on the MacBook.
Conclusion
If you encounter the disk Macintosh HD can’t be unlocked error, there is no need to worry! As it turns out, this is a fairly common issue. Simply follow these troubleshooting steps to get your MacBook turned on and functioning properly again:
- Run Disk Utility to repair disk errors
- Erase redundant disk volumes
- Reinstall macOS
- Reset NVRAM and PRAM
- Reset System Management Controller (SMC)
If you’ve completed each of these steps without success, check out the Apple MacBook Support page. You can also call the main Apple Customer Support line at 1-800-275-2273.
If all else fails, use your MacBook serial number to review your Apple warranty status.
Chelsea Ashbrook is a Senior Manager of Corporate Digital Experience at Genentech. Chelsea received her B.A. from the University of Connecticut and has spent the last 11 years working in the technology field.