Unable to create My F-Secure account with error "This email address is already in use" The "This email is already in use" error message indicates that you already have an existing My F-Secure account created with the email address. It is possible that you have created a My F-Secure account previously when trying out a trial product.
To be able to reuse your email address, first delete the old account and then create your account using this email address. To be able to delete the account, you first need to reset the My F-Secure password.