OK, I'm in OS10.2 disc utility, and it does not have Secure Erase Free Space option.
The sidebar shows 1 disc - a hardisc icon labelled 55.9GB, and 1 volume, hard disc icon with Macintosh HD label. Opening the erase tab displays a box in which all the options are greyed out and it is not possible to select or add anything. The disc utility box padlock is unlocked, so if should be able to use the erase tab, 10.2 permits it?
the erase tab box shows "volume format" as "Mac OS standard" and is greyed out, but there are arrows to select other options if it was not greyed out. There is a box for "name" below it, it is blank, but I can't write in it. There are "options" and "erase' buttons at bottom, but they too are greyed out.
Info in the box states that to erase a disc or volume, select the appropriate format and name and click the erase button. I have tried that, but all the options remain greyed out. Other info states that erasing a disc results is all volumes of that disc being erased and one large volume being created on that disc. Erasing a volume results in a clean volume being created.
This is where I got messed up before, OS10.2 does not seem to have a Secure Erase feature, at least I could not find it and I searched all over the system, even trying Help. So I made a DMG and filled it to the brim with everything on the computer until it nearly equaled the amount of available disc space, and then erased that -- evidently including user accounts.
So the question is, if Secure Erase is not part of OS10.2 and if the entire hard drive, including applications and system data were deleted, would that indicate that data is not recoverable, in light of fact that I have deleted my user accounts?