diff --git a/wp-includes/customize/class-wp-customize-site-icon-control.php b/wp-includes/customize/class-wp-customize-site-icon-control.php
index 7442fecaa2..9bbb7d1d61 100644
--- a/wp-includes/customize/class-wp-customize-site-icon-control.php
+++ b/wp-includes/customize/class-wp-customize-site-icon-control.php
@@ -59,7 +59,7 @@ class WP_Customize_Site_Icon_Control extends WP_Customize_Cropped_Image_Control
 			<# } #>
 		</label>
 
-		<# if ( data.attachment && data.attachment.id ) { #>
+		<# if ( data.attachment && data.attachment.id && data.attachment.sizes ) { #>
 			<div class="attachment-media-view">
 				<div class="site-icon-preview">
 					<div class="favicon-preview">
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d11c2ce534..8ad451d37c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37452';
+$wp_version = '4.6-alpha-37456';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.