Quote Originally Posted by nicksab View Post
My store does not allow guest checkout. Customer need to create an account in order to checkout.

I also notice the following:

If I log in as a customer with email/password (i.e. returning customer or new created account), then add a product to my cart. After going to checkout and go to edit shipping address, there is no "add to address book" box being displayed.
Yes, that was corrected in OPC v2.3.2.