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User profile for user: Hoop-Jump1
Hoop-Jump1 Author
User level: Level 1
4 points

Trying to erase disk on an old imac 2013

How to unmount MacHD? error code-69888


Posted on Apr 30, 2022 9:43 AM

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User profile for user: den.thed
den.thed
User level: Level 10
82,450 points

Posted on Apr 30, 2022 9:50 AM

Startup in macOS Recovery Mode and use Disk Utility to Erase the disk.

see > Use Disk Utility to erase an Intel-based Mac - Apple Support


The reinstall the macOS while in macOS Recovery Mode.

see > How to reinstall macOS - Apple Support

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Trying to erase disk on an old imac 2013

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