The disk “Macintosh HD — Data” can‘t be unlocked.

Had the same issue. In my case the Disk Utility was showing two "Data" volumes of the same size after upgrade.

One of the volumes was marked as Mac OS 11 volume but another one had no version indication so I just deleted it and the problem has gone.

shanshankar wrote:

Hi, Yesterday I have update MacOS BIG SUR. After login I got this 'The disk “Macintosh HD — Data” can‘t be unlocked.' A problem was detected with the disk, which prevents it from being unlocked.

popup message. How to resolve this issue?.

Thank,

Shan

Boot into Interent Recovery (Option Command R) and from the dropdown menu: Utilities>  Disk Utility> run the First Aid on your Macintosh HD (and the "Macintosh HD-Data" volume as well if Catalina/Big Sur) If errors are found and repaired, run again until no errors reported.

Disk Utility>View>Show All Devices The best sequence is —

• Volume level
• Container level
• Parent drive

ref: Recovery: https://support.apple.com/en-us/HT204904

How to erase a disk for Mac - https://support.apple.com/en-us/HT208496

How to reinstall macOS from macOS Recovery - https://support.apple.com/en-us/HT204904

Hi, I was updating my macbook to BIG SUR and faced with this. I was looking in many websites where users recommended to remove this partition, but in my case data on this partition was important and I've found the solution.

I did this: opened terminal and using diskutil found and UNLOCKED my partition. Just use "diskutil apfs unlockVolume /dev/disk..." command and enter passphrase after. I hope it will help you and others with same issue