Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have to give back a USB drive given to me from work that has some personal financial data on it. I already deleted the files, but when I look at recovery programs, they're still there! I've tried to "erase free space" in Disk Utility (35-pass erase) and Disk Drill can still find them. Is there any way I can permanently delete the data so nothing shows up in recovery programs?

share|improve this question
"Permanent Delete" and 35-pass zero-rewrite are only effective on magnetic media (spinning hard drives). On USB media you're just wearing out the solid state memory. Did you verify that you an actually recover the data you thought you deleted, or are you just seeing a reference to the file? – NReilingh Mar 16 '12 at 4:04

It's probably finding freed up references to the file names, but not the file contents. Format the drive with "zero out data" selected to ensure that even the directory data structures are completely purged of old file names.

share|improve this answer

I'm sure there would be a way to do this on Mac OS X as already mentioned, however it may be expedient to use another OS, securely wipe, then format back to Mac OS.

DBAN is a bootable cd and should securely erase your drive.

Just be sure to select the right drive...

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.