registration form requires a "name" ???

My reg form says "Please enter your name." when I hit the register button. But there is no field called "name" on the form. Where is this coming from? In the field management I can see this field but it is not even published.

You should have some form of name field present. Whether it's Name, First Name, Middle Name, Last Name, or a combination of the last 3. Re-save CB > Configuration and it'll auto-enable them as necessary. Be sure the "Name Style" parameter within CB > Configuration has a value as well. If still having issues check that at least one of the name fields is set to display on registration within CB > Field Management.

Thanks, but that is exactly what I don't want. I want a reg for with "username", "email" and "password" only, nothing else. So how do I switch off that "name" error?

Ensure none of the name fields are set to display on registration. CB will fallback to Username for the Name. If Username and Name are both missing then they'll both be set to Email Address. This doesn't prevent 3rd party plugins or Joomla user plugins from having issues with this though.

Thanks, but what exactly do you mean by issues with Joomla user plugins?

This doesn't prevent Joomla user plugins from having issues with this though.