Came across this today and thought I'd share another fix.
Find onepage.html in module-checkout
<!--
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
-->
<!-- ko foreach: getRegion('progressBar') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('estimation') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('messages') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<div class="opc-wrapper">
<ol class="opc" id="checkoutSteps">
<!-- ko foreach: getRegion('authentication') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('steps') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
</ol>
</div>
<!-- ko foreach: getRegion('sidebar') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
Move to your theme in Magento_Checkout/web/template/onepage.html
Move
<!-- ko foreach: getRegion('authentication') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
Into opc-wrapper or checkoutSteps like so:
<!--
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
-->
<!-- ko foreach: getRegion('progressBar') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('estimation') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('messages') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<div class="opc-wrapper">
<ol class="opc" id="checkoutSteps">
<!-- ko foreach: getRegion('authentication') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
<!-- ko foreach: getRegion('steps') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
</ol>
</div>
<!-- ko foreach: getRegion('sidebar') -->
<!-- ko template: getTemplate() --><!-- /ko -->
<!--/ko-->
Then copy authentication.html into your theme in Magento_Checkout/web/template/authentication.html
<button
type="button"
class="action action-auth-toggle"
data-trigger="authentication">
<span data-bind="i18n: 'Sign In'"></span>
</button>
And
style="display: none"
data-bind="mageInit: {
'Magento_Ui/js/modal/modal':{
'type': 'custom',
'modalClass': 'authentication-dropdown',
'trigger': '[data-trigger=authentication]',
'wrapperClass': 'authentication-wrapper',
'parentModalClass': '_has-modal-custom _has-auth-shown',
'responsive': true,
'responsiveClass': 'custom-slide',
'overlayClass': 'dropdown-overlay modal-custom-overlay',
'buttons': []
}}"
To disable the modal and style accordingly.