After messing about with Chrome OS on a USB stick, I found that I could not “clean” the disk with diskpart.  I tried deleting volumes, forcing formatting options with /recommended etc but nothing would work.

I was getting the following errors:

  • Error Parameter is Incorrect
  • Format error
  • DiskPart has encountered an error: The request could not be performed because of
    an I/O device error
  • DiskPart has encountered an error: Incorrect function

BAM then I found it.

convert gpt or convert mbr

After conversion, the disk would “clean” and format perfectly.  The following steps are what it took to make an unreadable, unformattable disk into a perfecly working USB thumb drive.

  1. Run the Command Prompt as Administrator.
  2. Run the DiskPart application (just type in diskpart)
  3. list disk  (check out which disk it is that you want to obliterate)
  4. select disk x (replace x with the disk number)
  5. detail disk (to see the current volumes on the disk)
  6. select volume x (select the volumes that you wish to delete (i deleted all that i could find))
  7. select disk x (make sure the disk that you are working on is definitely selected)
  8. Now for the bit that matters: convert gpt (converts the disk to gpt you can also use convert mbr depending on the system that you wish to use for this disk)
  9. You should now be able to “clean” the disk and create any partitions that you wish!



If this has helped you in any way please let me know.  Tweet @_BenjaminPeters or buy me a beer!