Disk macintosh HD - Data can't be unlocked - Big Sur

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Level 2

432 points

Disk macintosh HD - Data can't be unlocked - Big Sur

I just decided to make the jump on my MacBook to Big Sur (11.1), but every time I log in, I get the message : The disk ''Macintosh HD - Data'' can't be unlocked. Aproblem was detected with the disk that prevents it from being unlocked.

I'm reading about connected drives (external) : I don't have any disk connected at this time, and none would be named Macintosh HD - Data !!...

Does not seem to be a new issue as I read people who had this in first versions of Big Sur...

Posted on Jan 19, 2021 10:11 AM

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Answer 1

lanstrad1 Author

Level 2

432 points

Jan 20, 2021 9:23 PM in response to HWTech

Not sure this is what you asked me to do, but there it is after some 20 minutes of Internet recovery.

I see exactly what I saw before that 20 minutes boot up: there is a Macintosh HD - Data which is not mounted.

I don't know why there is such a greyed-out Macintosh HD - Data, and one that is mounted. As per my other message, that MBP was purchased from Apple about 2 months ago, barely served since then, and I just proceeded to upgrade to Big Sur few days ago.

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Answer 2

lanstrad1 Author

Level 2

432 points

Feb 20, 2021 10:08 AM in response to lanstrad1

I did a complete CLEAN reinstall of Big S..ur to clean that mess. Choosed to delete all volumes when formatted the hard drive.

Still : Surprise! ... The **** Data volume (greyed out) was still there when I finished reinstalling the OS and the prompt that it could not access that volume at login!!...

Bottom line: this time I just DELETED the volume through Disk Utility. Gone ! Ciao! I could have avoided myself 4-5 hours to do a USB bootable, backing up all data on external drive (that ''promised TB3 transfer that takes 2 hours to transfer 250 GB''... on a TB3 external drive...), performing the clean install and manual return of all data... just by doing so in the first place...

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Answer 3

HWTech

Level 9

60,230 points

Jan 19, 2021 9:26 PM in response to lanstrad1

What version of macOS were you using before v11.1?

How did you perform the upgrade?

My first thought is you installed Big Sur to the wrong Catalina volume. Boot into Recovery Mode (Command + R), Internet Recovery Mode (Command + Option + R), or from a bootable Big Sur USB installer and run the following command in the Terminal app located on the Utilities menu:

diskutil  list  internal

This will list all of the partitions and volumes on your internal drive (I'm assuming the internal drive is your boot drive). Post the output here.

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Answer 4

HWTech

Level 9

60,230 points

Jan 21, 2021 7:12 AM in response to lanstrad1

It is hard to say since the GUI version of Disk Utility limits what is shown (even when configured to "Show All Devices"). The command line output would make it easier to understand the layout although with Big Sur even this is now limited as well.

So far I have not used Big Sur with a Filevault encrypted volume so I'm not sure how Big Sur would handle it. Big Sur has made a lot of under the hood changes to how volumes are handled and put together most of which is hidden from view even within the normal terminal output of the command I suggested previously.

However, it appears that you have two separate "Data" volumes one of which is not currently mounted because it is encrypted. It is hard to tell from the picture whether both of these "Data" volumes have the exact same name (they should not). Is it possible that your drive is still being encrypted which may possibly explain the two "Data" volumes as being something new in the way Big Sur handles APFS volumes? Or maybe it is an APFS snapshot of the "Data" volume from before the Big Sur upgrade that somehow was made "active"? Normally when a user installs or reinstalls macOS 10.15+ they make the mistake of choosing the wrong volume for the installation which causes the macOS system volume to become "Macintosh HD - Data" and the new writable user volume where the user accounts are stored as "Macintosh HD - Data - Data", which doesn't seem to be the case here although it is hard to tell for sure.

I think this will be an extremely tough thing to troubleshoot and diagnose remotely since Big Sur has made so many undocumented changes to the way the underlying system works now and hides many things from view even when using the Terminal commands. I would say your best option is to erase the whole physical drive ("Apple SSD....") so you can perform a clean install, then migrate your stuff from a backup. Here is an Apple article with instructions for showing how to reveal the physical drive within Disk Utility:

https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/mac

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Answer 5

lanstrad1 Author

Level 2

432 points

Jan 19, 2021 10:35 PM in response to HWTech

I was under last Catalina update. This MBP is brand new (received from Apple about 2 months ago) so I dis not mess with creating volumes.

i proceeded to the upgrade just by okaying the prompt, dis nothing else than this.

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Answer 6

lanstrad1 Author

Level 2

432 points

Jan 21, 2021 9:32 PM in response to HWTech

Don't know if related, but tonight (2 days later), it looks like that system also made a big F. to my external HDD (LaCie rugged USB-C 5 TB) which has always worked fine (purchased 3 months ago), but suddenly does not appear in Finder, appears FULL in Disk Utility, and does the same on another Mac. I suspect that update f... my HDD. I'm out of the country, hope the Apple store here can honor paternity for both the MBP and the drive (also purchased at Apple online). Guess I'll pay them a visit. That may not save tons of precious stuff on that external HDD very unfortunately.

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Disk macintosh HD - Data can't be unlocked - Big Sur

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