Can't install Macos because disk is locked

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Can't install Macos because disk is locked

I had to upgrade my OS to load 2020 TurboTax. So attempted to download Big Sur on my well-functioning iMac 2017, but it failed and now my disks are locked and I cannot reinstall anything. I was able to reboot with High Sierra using an external hard drive, and tried to download High Sierra from Apple, but it failed also. Now my iMac HD is locked when I try to install any OS on it. How can I unlock it?

I rebooted using Command-R but don't see how to unlock in Disk Utility.

What do I do next?

iMac 27″, macOS 10.12

Posted on Feb 2, 2021 3:39 PM

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Answer 1

amwsin Author

Level 1

10 points

Feb 3, 2021 12:14 PM in response to HWTech

Here are my replies to your queries:

Did you have Filevault enabled on this Mac then?

- No Firevault enabled on this computer. Ever.

So you attempt to boot into Recovery Mode and you are presented with a request to provide a recovery key to unlock the drive?

Yes

Can you provide a picture of the screen where it is asking for the recovery key? If it has any drop down list boxes, then please click on it to reveal other possible options (if any) before taking the picture. I've only installed Big Sur once (lots of issues) and have not really explored much with it or experienced how its recovery mode may have changed.

No drop down menu.

What happens if you boot into Internet Recovery Mode using Command + Option + R?

I get to the screen with the spinning globe, asking me to choose Network
Once I type in my network to connect, then I get the SAME screen as the one above.

Thanks very much for your time and attention to this. I really appreciate it

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Answer 2

HWTech

Level 9

60,650 points

Feb 2, 2021 7:54 PM in response to amwsin

Did you have Filevault enabled on this Mac then?

So you attempt to boot into Recovery Mode and you are presented with a request to provide a recovery key to unlock the drive?

Can you provide a picture of the screen where it is asking for the recovery key? If it has any drop down list boxes, then please click on it to reveal other possible options (if any) before taking the picture. I've only installed Big Sur once (lots of issues) and have not really explored much with it or experienced how its recovery mode may have changed.

What happens if you boot into Internet Recovery Mode using Command + Option + R?

I'm working with another user on these forums who is having a similar need to restore from an APFS snapshot, but I'm not sure of the procedure when accessing the snapshot on a different volume. I'll see if I can make some time to experiment tomorrow so I can provide you with instructions for trying to use your High Sierra boot drive to restore the APFS snapshot on the iMac's internal drive.

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Answer 3

HWTech

Level 9

60,650 points

Feb 2, 2021 4:56 PM in response to amwsin

Apple has been having issues with downloading the macOS installers from the App Store for the last few days.

You can try restoring the iMac to its previous state by booting into Recovery Mode or Internet Recovery Mode and selecting the "Restore from Time Machine backup". You should be able to select a local APFS snapshot that the Big Sur installer should have made as it began to upgrade your Mac.

When you boot into Recovery Mode which version of the macOS installer is being accessed?

If you can boot your iMac with the external drive, then I highly recommend you make sure to have any important data copied to another location just in case something goes wrong with this process or with any attempt to restore macOS.

Make sure to always have frequent and regular backups.

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Answer 4

amwsin Author

Level 1

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Feb 2, 2021 5:21 PM in response to HWTech

Thank you. The macOS appears to be 10.13.6.

I have rebooted into Recovery Mode and see the macOS Recovery window, with the request: Enter recovery key to unlock the volume "Macintosh HD"

As far as I know I have never generated a recovery code. How do I do so?

(I had all my files backed up, but not the system.)

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Answer 5

HWTech

Level 9

60,650 points

Feb 2, 2021 6:14 PM in response to amwsin

Usually you have the option to use a recovery key or an authorized user account on that Mac to unlock the volume, although I have been finding lots of weird unexpected behaviors with various authentication methods employed by Apple on their 2018+ T2 Macs.

Are you still booting into Recovery Mode or have you reached the screen with various options such as Restore from TM, Install macOS, Disk Utility? If you have reached the latter screen, then try launching Disk Utility and manually mounting the volume to unlock it. If successful, then quit Disk Utility and select the "Restore from Time Machine".

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Answer 6

amwsin Author

Level 1

10 points

Feb 2, 2021 7:22 PM in response to HWTech

Before I submitting my question here, I had been trying solutions to unlocking the drive that I found online. I had booted up using the OS on my eternal drive, and tried a clean reinstall that erased the HD to start over.

The only option is the recovery key. on the screen produced in the recovery mode.

I found a 24-character string I had marked as a "code" that I thought might be the recovery key for the "Macintosh HD," but then I read on Apple that recovery codes were 28 characters. Anyway, when I tried it, it did not work.

Message: "The supplied password failed to unlock the disk. "

So I cannot get past that screen in recovery mode.

I had always been able to get to the page with the four options: Restore from Time Machine, Reinstall OS system, Disk Utilities and whatever, but this time when I restart (without my external drive with the OS,) I don't get to that page at all, but only reach a black screen with the flashing ? folder. At the bottom is: support.apple.com/mac/startup

Does that mean my HD is shot or just not accessible?

I have now tried First Aid on my Macintosh HD and it says it could not unmount it for repair

Everything was working well before I tried to download Big Sur.

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Answer 7

HWTech

Level 9

60,650 points

Feb 3, 2021 12:42 PM in response to amwsin

I've never seen that screen before even with a Filevault encrypted drive. It seems like you may be using your AppleID to log in with this device or have FindMy turned on. I don't have any experience with having either one activated on the Macs I've repaired and I don't know how those particular security measures work regarding Recovery Mode. Unfortunately since this laptop isn't booting to its main drive I'm not sure either one can be deactivated.

I haven't had time yet today to experiment with trying to work with an APFS snapshot while booted from an external drive.

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Can't install Macos because disk is locked

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