Hi BrianLaseby,
I'm Paul, a Microsoft Community Member, and a Windows expert. I hope I can help you with your concern
Please try to use the DIskpart.
- Open Command Prompt as an administrator.
- At the command prompt, enter diskpart.
- Enter list disk.
- Enter select disk ( flash drive letter).
- Enter clean.
- Enter create partition primary.
- Enter select partition 1.
- Enter active.
- Enter format fs=fat32.
- Enter exit.
I hope this helps. Feel free to ask back any questions and keep me posted.