How can I re-format a thumb drive back to MS-DOS(FAT)

Question

I bought a kingston 16gb thumb drive today, and formatted it to Mac OS X Extended (Journaled, Encrypted) using the disk utility. I was unaware that it will not work with a PC now, only Mac. Is there a way to covert it back to MS-DOS or am I going to have to partion it? I tried to re-format it, but MS-DOS is no longer an option from the drop down menu. Any input is appreciated.

Answer 1

I also had similar problems and just figured it out this afternoon. This is what you're going to do. Open Terminal. It's under Applications>Utilities>Terminal and then type in:
diskutil cs list
This will bring up something like this
CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 109FC023-5F18-438A-AF3D-14FF60334A0C
   =========================================================
   Name: Le Disque
   Size: 68375502848 B (68.4 GB)
   Free Space: 0 B (0 B)
   |
You will want to find the name of the device (Whatever you named your kingston 16gb thumb drive) and copy the Logical Volume Group ID code. An example from above would be coping the code:
109FC023-5F18-438A-AF3D-14FF60334A0C
That is called the UUID.
Warning The next command will erase the disk specified by the UUID you enter. Make sure you've copied the correct Logical Volume Group UUID for the disk you want to erase, especially if you have more than one encrypted disk connected.
After you have that code, you will then want to type into Terminal
diskutil cs delete copiedUUID
Remember to replace the "copiedUUID" part with the code you copied earlier.Using the example above, it would be
diskutil cs delete 109FC023-5F18-438A-AF3D-14FF60334A0C
Let it run.
After that, the device will now be called "Untitled" and you will be able to format it back to MS-DOT(FAT) using the Disk Utilities application.
Hope this helps.
Reference:
http://apple.stackexchange.com/questions/26259/lost-password-on-mac-os-extended- journaled-encrypted-drive-want-to-reformat