I use USB Drives quite a bit to move data between Windows, Mac and Linux Devices.  Sometimes when i go to re-format them they only show as 200MB capacity

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As I’m on a Windows machine, open the Command Prompt (CMD) and type: diskpart

Type: list disk to see your drive, in my case here, its Disk 2

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Type: select disk <insert disk number> so in my case select disk 2

type: clean this will zero down the drive

Close down the disk part window and open Disk Management

The Drive will appear as Unallocated

Right click the Drive and Select New Simple Volume

Follow the wizard through ensuring you select the correct File System type – In my case I will leave as Fat32