Username is "taken" but doesn't exist?

A memeber just joined my forum (AMF) and wanted to use the name Windsor.

No users with this name exist, yet it says the name is taken. I can't change his name to Windsor or find a user with that name.
Any reason why?

Thanks,
Null-11

i would guess he has attemted to join a few times and made mistakes that would mean the username is taken, go to users and groups and click inactive users, you could find him there a few times over, delete them and let him start again

Thanks.

Thanks! This fixes my problem from a previous post.

-Metina

I pulled this from another forum questions.

"I would guess he has attemted to join a few times and made mistakes that would mean the username is taken, go to users and groups and click inactive users, you could find him there a few times over, delete them and let him start again."