Unfortunately I'm having to return my new Mac Pro, one month old. It has logic board problems. Kudos to Apple for their first suggestion, "Jim, would you like to exchange it for a new one?" "Heck yes!" I said. Anyway, I have 4 internal 1TB drives that I need to zero out. One zero pass on one drive takes 3+ hours. I would like to do a 7 pass on each drive, but that would take four days (90 hours) by my count before I could ship it back. And I want my new Mac asap! Question? The most each drive contained was 500GB's. Can I do a zero pass on a drive and stop it approximately halfway through (hit Skip button) and then repeat the (half) process over again as often as I desire. Will my half used drives and/or data be zeroed out multiple times. If so this would save me many hours of zeroing out half empty drives! Hope I made myself clear, if not, let me know, OK? Thanks for a great forum, Jim ;o) Edit; Man, do I ever get long winded sometimes! In short, what effect does a partial zero pass have on a hard drive?