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Umount hd

Trying reinstall Yosemite 10.10 2009 iMac. Erase hd getting “couldn’t unmount disk”

Posted on Jun 6, 2022 6:56 AM

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Accidently deleted Macintosh HD on Disk Utility - now my mac won't start up Earlier today I was trying to reset my Macbook Pro (2016 model on MacOS Big Sur) to sell and I deleted Macintosh HD from the Disk Utility software thinking that it would reset my mac to factory settings. Now my Mac can't start up and shows a folder with a question mark in it. First Aid does not work for any of the internal options. "Preboot", "Recovery" and "VM" are unmounted every time I go back in to Disk Utility. First Aid for Internal > AppleAPFSMedia does not work and says I need to repair the startup volume by running First Aid from Recovery? Isn't that what I'm doing? When I try re-install MacOS it only shows "Macintosh HD - Data" & "Update" and the installation always fails when reaching the end on either option. Attached is a photo of my Internal disks on Disk Utility. I would appreciate any help, thank you in advance!
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1 reply

Owl-53

Level 10

123,805 points

Jun 6, 2022 7:17 AM in response to nestafromcastlegar

Use Disk Utility to erase an Intel-based Mac as per Apple Support

How to reinstall macOS also as per Apple Support

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Umount hd