The Windows Disk Management utility (available in Computer Management) is a very easy to use tool for basic partition creation and deletion on secondary drives. However, it struggles whenever there is a partition with an ‘unknown’ or ‘foreign’ format, such as on OEM utility partitions. Using Disk Management, you can delete/format all other partitions on the drive, but just not those.

To easily remove these partitions without having run special software or boot to a hard drive utility, use the Diskpart tool included with Windows. The process would go something like this:

  • >list disk (a list of all the hard drives will be displayed)
  • >select disk # (where # is the disk number from the list which has the unknown partition)
  • >list partition (a list of all the partitions on the selected disk will appear)
  • >select partition # (where # is the partition number of the unknown partition)
  • >delete partition override (it should now be gone)

Once you do this, if you open Disk Management, you should see the previously un-deletable partition is now gone. This is a handy way to save you some time (and software installs) when you need to do this really simple task.