How to make sure old files are eliminated from a Mac hard drive?

Factual Questions
1

I have an old iMac G5 that I’d like to pass down to someone, but I’d like to make sure my information is gone from it.

Complications:

  • I’ve lost the system install disc, so I can’t just wipe and reinstall the OS

  • It’s too old to be upgraded to the current system - it runs on 10.5 and won’t be able to upgrade to the system discs that I actually do have
    What I’ve done already:

  • Created a new admin account and deleted all the old accounts on the computer. But I suspect this just makes things less visible rather than actually erasing them.

What should I do to make sure that old tax returns and info to access iTunes acct, etc. is actually not recoverable?

2

I believe Leopard’s Disk Utility app had the ability to “Erase free space.”
Look in /Applications/Utilities for Disk Utility, launch it, and see.

3

It does! Thanks very much beowulff. :slight_smile:

4

If you want to actually scrub a drive, rather than just erase files, DBAN is what you want.

5

Does it run on OS X?
No.

The “Erase Free Space” option in Disk Utilities overwrites deleted files with zeros, and is good enough for anyone but the NSA (and probably even they couldn’t recover files erased using it).

6

If he does not have the system restore disk, he does not want DBAN, since it will wipe the whole drive.

Mac OS X Disk Utility supports both erasing free space, and erasing the entire drive a la DBAN. It also supports more complicated schemes than simply writing zeros - I think it has a 7-pass option that will writing alternating sequences of 1s and 0s, etc.