Can't reinstall Big Sur from recovery mode, won't allow me to select system disk

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Level 1

20 points

I am attempting to re-install Big Sur 11.3 from recovery mode on my system disk.

When selecting my internal disk when attempting to do this, I receive the following error:

The operation couldn't be completed. (com.apple.BuildInfo.preflight.error error 21.)

Have no idea what it could be, searches weren't any help.

Troubleshooting steps already tried to no avail:

I'm at a loss as to what to do next, or even knowing what's causing the error, let alone how to fix it. Hoping someone can help!

Mac mini 2018 or later

Posted on May 1, 2021 5:19 AM

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Answer 1

Best reply

Level 8

45,706 points

If you just want to Reinstall, follow these steps:

Shut down the Mac.
Turn on the Mac, and immediately press and hold Option + Command + R until you see a spinning globe.
Once you are in macOS Recovery, verify you are connected to WiFi in the top right corner.
Go to the reinstall macOS app.
Follow the prompts, and install on Macintosh HD.

If you just want to Reinstall and erase your Mac, follow these steps:

Shut down the Mac.
Turn on the Mac, and immediately press and hold Option + Command + R until you see a spinning globe.
Once you are in macOS Recovery, verify you are connected to WiFi in the top right corner.
Go to Disk Utility.
Select "View" in the toolbar —> "Show All Devices".
Select your main hard drive or SSD. This will be the top, non indented hard drive.
Click Erase, and input the following exactly: (If you cannot select erase on the main hard drive, erase the "Container" or “Macintosh HD”.)
Name: Macintosh HD
Format: APFS
Scheme: GUID Partition Map (if shown)
Click Erase. If “Erase Volume Group” is shown, use that instead.
Quit Disk Utility
Go to the reinstall macOS app.
Follow the prompts, and install on Macintosh HD.

Cheers,

Jack

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