Disk utility can't unmout External Drive

[abiteoftheapple]

Hi all

My macBook can't unmount my External Hard drive in Disk utility when I try to erase all the data on it. I get a message :

Disk erase failed

Disk Erase failed with the error:

Could not unmount disk


And when I try to erase folders on the disk I get a message :

The operation can’t be completed because one or more required items can’t be found.
(Error code -43)

Any ideas ?
Please help,

 

[Hellhammer]

Boot from the install disc and use its Disk Utility. I've had this same issue but that method has never failed.

 

[abiteoftheapple]

The Mac OSX install disk ?

Sorry kinda new,
Thanks

 

[Hellhammer]

The Mac OSX install disk ?

Sorry kinda new,
Thanks

Yes. The grey discs that came with your Mac.

 

[abiteoftheapple]

Okay, need to find them first

Thank you very much.