Secure disk wipe with Windows format command

From Windows 8 Microsoft snuck in a refinement to the format command. It is now possible to get it to do multi-pass random-number disk wipes. From the help (Win 10 20H2):

 /P:count  Zero every sector on the volume. After that, the volume
           will be overwritten "count" times using a different
           random number each time. If "count" is zero, no additional
           overwrites are made after zeroing every sector. This switch
           is ignored when /Q is specified.

So to do a single-pass random wipe:

  • Repartition disk with one partition (if desired) and give it a drive letter (let’s say F for this example). Probably a good idea to remove any OEM, EFI, recovery partitions like this. A quick way to do this is to use the clean command in diskpart.
  • Run format F: /P:1
  • If you feel like it finish up with a clean command in diskpart.

This should do a pass with all zeros, and then a random-number pass.

Note this isn’t a full ‘write random data to every block in the drive’ erase, but should still be secure enough for most purposes.

Published by

Jamie Scott

IT Administrator at the Institute for Gravitational Research, University of Glasgow