Make new order without email

Hi there!
Now, if i make a new order completing with any email (no registration), but after a while i want to make an account with the same email, it says that email is already used. So, is there any possibility to make an order withot registration but not to add that email in the detabase?

Doesn't guest checkout give you want you want. I'm pretty sure guest checkout doesn't create logins unless you've applied a mod.

No, guest checkout doesn't do that. You'd need to create another table to store GUEST CHECKOUT EMAILS so they don't conflict with normal registration. Then you can use these emails at will, later.