Disk Utility - "Security Options" grayed out

[macman221285]

Hi,

I am trying to 'Erase free space' using the disk utility on my macbook. I have read that you can choose to 'overwrite with zeros' via the 'Security options' tab. However, my 'security options' tab is grayed out (see pic below). Please can you tell me how I can access the 'security options' and therefore free the disk space and overwrite with zeros??

 

[zrbecker]

The security options are for erasing the entire volume. If you just use "Erase Free Space" then it will overwrite your free space with zeros.

Source: http://docs.info.apple.com/article.html?path=diskutility/10.5/en/duh1010.html