Erase function doesn’t work on Macintosh HD volume inside Disk Utility

kaz-k wrote:

Hi,

Start up in Recovery Mode, then use DiskUtility to erase Macintosh HD as well as Macintosh HD Data.

How to reinstall macOS - Apple Support

Make sure to do one of the following in Disk Utility:

• If you select Macintosh HD and click Erase: Make sure that you are erasing the volume group, and not just the individual volume.

• Completely delete (not erase) Macintosh HD - Data. (It could also be named just "Data".)

What to do before you sell, give away, or trade in your Mac

The above will achieve the desired results even if not selling, giving it away

Trying to erase hard rive on 9 yr old iMac, using Disk Utility per instructions. Error message: "Erase process has failed. The volume "Macintosh HD on disk3x5 couldn't be unmounted because it is in use by process 692 (kextcache).

Couldn't unmount disk.: (-69888)

Operation Failed..."

What do I do now?

Hi,

Start up in Recovery Mode, then use DiskUtility to erase Macintosh HD as well as Macintosh HD Data.

How to reinstall macOS - Apple Support

I restarted it in recovery mode, went to Disk Utility and it erased this time.