The Disk “Macintosh HD-Data” Can’t Be Unlocked – Here’s the fix with Big Sur

Last Updated on Jan 5, 2021

Know why your mac saying Macintosh HD-Data” Can’t Be Unlocked on startup and After Reinstall or Upgrade to MacOS Version to latest one. Now a Days macOS Big Sur users are getting this error popup messages on the screen every time when turning on and logging in to Mac or MacBook. Most people affected by this error due to Beta and Public macOS installed [macOS Big Sur] on separate Partition on the same Mac, MacBook Drive.

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The Warning message on the screen is “The Disk “Macintosh HD – Data” can’t be unlocked. A problem was detected with the disk that prevents it from being unlocked.

What Does Affect on Mac Behind this Problem?

We will fix the problem in two ways, First is Normal mode and the second is in recovery mode,

1). Fix macOS Partition on Mac Disk

This Error or Warning message is saying that your Mac is in a problem to open a disk partition, So your mac has too many or more than one Disk Partition for Install MacOS. and You have to Re-install macOS On another Partition. In this can you have to identify active or Needed partition then delete unused another Partition.

  1. Open Finder on Mac > From Top Mac Menu Go > Utility.

    Open Utilities on Mac from finder

    Open Utilities on Mac from finder

  2. Find “Disk Utility” and Open it.

    Open Disk Utilities on Mac

    Open Disk Utilities on Mac

  3. Now, Click on View > “Show Sidebar” and “Show All Devices“.

    Show Sidebar and Devices

    Show Sidebar and Devices

  4. Select the Disk Volumes Partition from the sidebar of the Disk Utility window.
  5. Normally, We can’t Delete Macintosh HD-Data or MacOS-Data Volume, because it contains User’s Data. So we will repair it first. then the problem is not fixed then Erase the Unused or Duplicate Partition [Backup first before erase]. Get a Detailed Explanation in this article.

    First Aid and Erase Duplicated macOS Partition on Mac

    First Aid and Erase Duplicated macOS Partition on Mac

But if you have more than one redundant Volume then you can do it. Volumes likes,

“Macintosh HD”
“Macintosh HD – Data”
“Macintosh HD – Data Data”

If you Won’t able to Repair [First-Aid] Volume from Mac, then Erase the Apple Drive and Re-install a new copy of macOS. later on, we will see how to do it? in this article, Before the move to the next important steps if Backup the Data Using Time Machine.

Backup Mac Data on Time Machine to External Drive

Backup Mac Data on Time Machine to External Drive

Just select the Unused Volume partition and Select (-) from the top Tab in a window.

Here you have to go with the “Delete” option, Note: Don’t Delete All Groups of volume.

2) Backup Mac Data

Backup of your Mac Data must be a critical step because this problem we can’t figure out without deleting the Volume partition and Re-installation of your Mac. So you will lose the data. I recommend taking a Time Machine backup to External Drive.

  • Go to the Apple Logo > System Preferences > Time Machine > Select Drive and Start Time machine backup.

Once you backup on External Drive, you can Repair the Partition and Volume at any level. Let’s start with Repair Specific Volumes one by one.

3). First Aid – Repair the Drive From Disk Utility

Repair the Volume option delete the internal system error and repair itself. Sometimes, it’s time-consuming that depends on the Data size saved on your Mac’s drive.

  1. Open Disk Utility Window > Now, Click on View > “Show Sidebar” and “Show All Devices” on Mac.
  2. Select the Volume from sidebar > and Click on the First aid option to start the repairing process.

Won’t Repair First Aid or Takes a time to Complete the repair process

Many users were found this solution is not helped them. Try the next solution if it does not work for you.

4). Erase Volume Partition

Before starting the Erasing process you have to check and identify which Volume Partition Data folder is in use. Because you have to Erase the Duplicate Machintosh HD Data Volume only.

  1. Open “Finder” on Mac > From top Mac menu Click on “Go” > “Utilities” > and Open “Disk Utility“.
  2. Now, Click on View > “Show Sidebar” and “Show All Devices” on Mac.
  3. Find Using MacOS Version installed on your Mac’s Partition. Select Unused or Duplicated Volume partition, then Select Erase option from top options on a window.

    Know macOS Version installed on Selected Partition on Mac

    Know macOS Version installed on Selected Partition on Mac

Note: if your Mac won’t log in or unable to start then perform repair and erase the partition in recovery mode.

Go Through macOS Recovery and Fix the issues

Enter your Mac into MacOS Recovery, Perform all the repair, Reinstall or Erase the Duplicate drive from the macOS Recovery window.

Run First Aid:-

if you are in recovery mode then you will see the macOS Utility screen, Select “Disk Utility” Option > “Continue“.

Select the volume from the sidebar and run first aid.

or To Erase the Drive,

Select the volume from the sidebar from Disk Utility and Select Erase from the top of the window.

In the same way, we can Erase Apple Drive completely using Disk Utility to remove all unused Volumes and Partition from mac SSD or HDD internal drive.

Then Re-install new macOS on Your Mac. Start your Mac > Press Command + R key to See macOS Recovery Window > Select install macOS, Your Mac will download lateset macOS from internet and install.

Later on, we can restore all types of Data to Mac without any Data loss using time machine backup.

Won’t more help from us, then comment me on below comment box or Contact apple Support at Genius bar reservation.

Jaysukh Patel is the founder of howtoisolve. Also self Professional Developer, Techno lover mainly for iPhone, iPad, iPod Touch and iOS, Jaysukh is one of responsible person in his family. Contact On: [email protected] [OR] [email protected]

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