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jasonkstupski

macrumors newbie
Original poster
Aug 4, 2009
3
0
Hello,

I'm booted on a MacBook Pro from an external drive, and I want to erase the drive inside the MacBook using Disk Utility from the external. For some reason or another, it won't let me do this.

When I click on the Erase tab (whether clicked on the disk itself or the volume "Macintosh HD") and try to erase it, it returns with the error:

Disk Erase failed
Disk Erase failed with the error:

Could not unmount disk.

When I try to install an image onto the drive, I get a similar error, except it says "Operation not permitted."

When I tried it while booted with an OS X DVD, it worked fine.

As far as I know, I should be able to do this while booted from the external HD.

Any solutions to this problem?

Thanks,
Jason
 
Solved - I had launched Disk Utility from the internal drive using Spotlight instead of from the External Drive.
 
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