MacKid1983

macrumors 6502
Original poster
Oct 1, 2011
305
21
I have a MBP and trying to erase my HDD and I get an error "Disk Erase Failed' Could not unmount disk.

I have lion. Any Suggestions? I want to sell my Mac.
 

thebritishguy

macrumors member
Dec 30, 2011
56
0
Make sure spotlight is not indexing, i recently had exactly the same issue when i installed a second drive, you should also restart finder using Alt, command, esc
 
Nov 28, 2010
22,670
28
located
I have a MBP and trying to erase my HDD and I get an error "Disk Erase Failed' Could not unmount disk.

I have lion. Any Suggestions? I want to sell my Mac.


____________________________________________________________

Links to guides on how to use Disk Utility, the application Mac OS X provides for managing internal and external HDD/SSDs and its formats.
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Make sure spotlight is not indexing, i recently had exactly the same issue when i installed a second drive, you should also restart finder using Alt, command, esc

What does that have to do with the OP's question?
Ah, I see, that that is your first post.
 

MacKid1983

macrumors 6502
Original poster
Oct 1, 2011
305
21
I *think* i booted from the flash drive.....

I have a flash drive with a Lion on it, Installed lion and copied the "install.dmg" and I want to erase my hdd with a few passes and re-install lion.

I started my computer while holding down "COMMAND R" and opened disk utility and wanted to erase the hdd that way.

But I just read on a site to do this: "Restart your computer by holding down the option key. You will now be given an option to boot from the DVD or USB drive. Go through the installation, ready to enjoy a new, clean install of Lion."

Am I restarting the incorrect way? But before I re-install lion I want to erase the HDD"

I read some of the articles simsaladimbamba posted but I dont quite get what "To format, erase, or reformat your Startup volume (the OSX volume on your internal HD), you must start your Mac up from a different source: •On Lion, the Recovery HD or OSX USB thumb drive."

Thats what I am doing, by restarting my Mac while holding down "COMMAND R". Or do I just hold down
 
Last edited:

Mal

macrumors 603
Jan 6, 2002
6,249
17
Orlando
Your flash drive is being completely ignored if you're holding down Command R on restart, because that boots from the recovery partition (or internet recovery if you have a model that doesn't have the recovery partition). Hold option to boot from the flash drive, assuming you set it up correctly, and you can use Disk Utility from there to erase your hard drive.

jW
 
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