Required checkbox during registration

We were able to reproduce the problem on our end. We'll look at how we can correct it tomorrow.

You need to replace the file media/com_hikashop/hikashop.js by the one in this archive and change the line:
if(!$field->field_required || strlen($value) || strlen($oldvalue)){
by:
if(!$field->field_required || is_array($value) || strlen($value) || strlen($oldvalue)){

in the file administrator/components/com_hikashop/classes/field.php

That should make it work.

That modification was included in HikaShop.
I just tested it on our demo website and I can't register unless I check the required checkbox of the form so it works.

What do you mean by you have registration off ? If the registration is disabled on your website, you should not see the registration form at all and you should see instead a message telling the user that the registration is disabled...

Could you give a link ?

I can't login on your htaccess authentication. Could you double check the username and password please ?

You don't have any checkbox custom field on your registration form. What you have is the terms view. The terms view is only checked at the end of the checkout and it works fine on your checkout. When I arrive at the end of the checkout, if I didn't tick the terms checkbox, I get the message:
Please accept the terms and conditions before proceeding
and I'm redirected to the step where I can do that.

The terms and conditions view of the checkout is there to ensure that the user accepts them before finishing his order, not for the registration.
If you want a terms checkbox for the registration, you should create a new custom field of the table "user" of the type "checkbox" and required instead of using that view and the users won't be able to register unless they tick that checkbox.

Sure. You need to change your checkout workflow for that. You can move the view fields_ from the last step to the first step and voilà.

I understand but that's not how the system is done... If you want you can directly edit the file components/com_hikashop/controllers/checkout.php and change the code:
function after_terms(){
$app =& JFactory::getApplication();
$app->setUserState( HIKASHOP_COMPONENT.'.checkout_terms', JRequest::getInt('hikashop_checkout_terms',0) );
return true;
}

to:
function after_terms(){
$app =& JFactory::getApplication();
$app->setUserState( HIKASHOP_COMPONENT.'.checkout_terms', JRequest::getInt('hikashop_checkout_terms',0) );
return $this->check_terms();
}

Did you put the terms view on the first step of the checkout workflow ?

The terms checkbox is displayed by the terms file of the view checkout.

What you could do is to edit the file step of the view checkout and add a javascript check on the next button in order to forbid the user to go to the next step if he doesn't check the terms and conditions.