I recently used my SanDisk Cruzer USB flash drive as a rescue disk for my Chromebook while I was playing around in developer mode with crouton and ChrUbuntu in the event something went horribly wrong. Fortunately all went well and I wound up not needing to use it; however, today I went to throw some files on it and thought a simple reformat would do the trick.
Well if you're reading this article chances are you've realized that this it's not this easy. When I plugged it in windows asked me to format before I went in to do the format myself. Kudos Microsoft....wait what's this 2 megabyte partition size? I canceled the format and went into the windows disk manager and saw around a dozen or so volumes of random size. Well shit, I guess I'll just delete all these volumes then make a new volume and be done. Well on about the 3rd volume I tried to erase I noticed there was no delete volume option. Argh...
Well time to delve into the console and fire up good ol' fdisk and try to kill off this stuff the old fashioned way. Then to my surprise I found that fdisk doesn't exist anymore. Surprisingly this was discontinued back around the XP era so apparently I haven't needed to fire up fdisk in quite some years. Anyway, the replacement utility is called diskpart and was fine. Enter diskpart...
Once you have started diskpart run a list disk command and find your USB drive.
DISKPART> list disk
Disk ### Status Size Free
Disk 0 Online 596GB 0B
Disk 1 Online 7644MB 7543MB
My flash drive is 8GB so the 7644MB "Disk 1" is clearly it.
DISKPART> select disk 1
It is critical you select your USB flash drive. If you don't know which drive to select ask your local geek to help you out. Once the disk has been selected run "detail disk" to verify you have the correct disk selected. You should see something like this:
Again, verify this is the correct disk or seek help from a geek friend!!! Once you have verified that you have selected the correct drive you can destroy all sectors on the disk using the diskpart's secure erase command "clean all" This will destroy ALL data on the disk and make it completely unrecoverable. This process will take some time to complete. My 8gb flash drive took ~15 minutes.
DISKPART> clean all
Once this completes you can go into the normal windows disk management tool and create a new volume using your freshly emptied flash drive.