diff --git src/wp-admin/custom-header.php src/wp-admin/custom-header.php
index c1a7896589..a8ca1d527b 100644
--- src/wp-admin/custom-header.php
+++ src/wp-admin/custom-header.php
@@ -758,7 +758,7 @@ wp_nonce_field( 'custom-header-options', '_wpnonce-custom-header-options' );
 		check_admin_referer( 'custom-header-upload', '_wpnonce-custom-header-upload' );
 		if ( ! current_theme_supports( 'custom-header', 'uploads' ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 				'<p>' . __( 'The current theme does not support uploading a custom header image.' ) . '</p>',
 				403
 			);
@@ -922,7 +922,7 @@ wp_nonce_field( 'custom-header-options', '_wpnonce-custom-header-options' );
 
 		if ( ! current_theme_supports( 'custom-header', 'uploads' ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 				'<p>' . __( 'The current theme does not support uploading a custom header image.' ) . '</p>',
 				403
 			);
@@ -930,7 +930,7 @@ wp_nonce_field( 'custom-header-options', '_wpnonce-custom-header-options' );
 
 		if ( ! empty( $_POST['skip-cropping'] ) && ! ( current_theme_supports( 'custom-header', 'flex-height' ) || current_theme_supports( 'custom-header', 'flex-width' ) ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 				'<p>' . __( 'The current theme does not support a flexible sized header image.' ) . '</p>',
 				403
 			);
diff --git src/wp-admin/customize.php src/wp-admin/customize.php
index e54e2170bb..0101ee25a7 100644
--- src/wp-admin/customize.php
+++ src/wp-admin/customize.php
@@ -14,7 +14,7 @@ require_once( dirname( __FILE__ ) . '/admin.php' );
 
 if ( ! current_user_can( 'customize' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to customize this site.' ) . '</p>',
 		403
 	);
@@ -31,7 +31,7 @@ if ( $wp_customize->changeset_post_id() ) {
 
 	if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post->ID ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 			'<p>' . __( 'Sorry, you are not allowed to edit this changeset.' ) . '</p>',
 			403
 		);
@@ -76,7 +76,7 @@ if ( $wp_customize->changeset_post_id() ) {
 
 	if ( in_array( get_post_status( $changeset_post->ID ), array( 'publish', 'trash' ), true ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 			'<p>' . __( 'This changeset cannot be further modified.' ) . '</p>' .
 			'<p><a href="' . esc_url( remove_query_arg( 'changeset_uuid' ) ) . '">' . __( 'Customize New Changes' ) . '</a></p>',
 			403
diff --git src/wp-admin/edit-comments.php src/wp-admin/edit-comments.php
index 85c04ead57..6b2d4af1be 100644
--- src/wp-admin/edit-comments.php
+++ src/wp-admin/edit-comments.php
@@ -10,7 +10,7 @@
 require_once( dirname( __FILE__ ) . '/admin.php' );
 if ( ! current_user_can( 'edit_posts' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit comments.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/edit-tags.php src/wp-admin/edit-tags.php
index c49b61b2cb..41e63abd43 100644
--- src/wp-admin/edit-tags.php
+++ src/wp-admin/edit-tags.php
@@ -25,7 +25,7 @@ if ( ! in_array( $tax->name, get_taxonomies( array( 'show_ui' => true ) ) ) ) {
 
 if ( ! current_user_can( $tax->cap->manage_terms ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to manage terms in this taxonomy.' ) . '</p>',
 		403
 	);
@@ -81,7 +81,7 @@ switch ( $wp_list_table->current_action() ) {
 
 		if ( ! current_user_can( $tax->cap->edit_terms ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 				'<p>' . __( 'Sorry, you are not allowed to create terms in this taxonomy.' ) . '</p>',
 				403
 			);
@@ -111,7 +111,7 @@ switch ( $wp_list_table->current_action() ) {
 
 		if ( ! current_user_can( 'delete_term', $tag_ID ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 				'<p>' . __( 'Sorry, you are not allowed to delete this item.' ) . '</p>',
 				403
 			);
@@ -131,7 +131,7 @@ switch ( $wp_list_table->current_action() ) {
 
 		if ( ! current_user_can( $tax->cap->delete_terms ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 				'<p>' . __( 'Sorry, you are not allowed to delete these items.' ) . '</p>',
 				403
 			);
@@ -167,7 +167,7 @@ switch ( $wp_list_table->current_action() ) {
 
 		if ( ! current_user_can( 'edit_term', $tag_ID ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 				'<p>' . __( 'Sorry, you are not allowed to edit this item.' ) . '</p>',
 				403
 			);
diff --git src/wp-admin/edit.php src/wp-admin/edit.php
index f629734c18..a05d369e1d 100644
--- src/wp-admin/edit.php
+++ src/wp-admin/edit.php
@@ -38,7 +38,7 @@ if ( ! $post_type_object ) {
 
 if ( ! current_user_can( $post_type_object->cap->edit_posts ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit posts in this post type.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/includes/bookmark.php src/wp-admin/includes/bookmark.php
index 285d716c2a..571dff3c3b 100644
--- src/wp-admin/includes/bookmark.php
+++ src/wp-admin/includes/bookmark.php
@@ -28,7 +28,7 @@ function add_link() {
 function edit_link( $link_id = 0 ) {
 	if ( ! current_user_can( 'manage_links' ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 			'<p>' . __( 'Sorry, you are not allowed to edit the links for this site.' ) . '</p>',
 			403
 		);
diff --git src/wp-admin/includes/file.php src/wp-admin/includes/file.php
index fe05085dd8..2b1c5b1864 100644
--- src/wp-admin/includes/file.php
+++ src/wp-admin/includes/file.php
@@ -591,7 +591,7 @@ function wp_edit_theme_plugin_file( $args ) {
 			}
 
 			if ( ! isset( $result['message'] ) ) {
-				$message = __( 'An unidentified error has occurred.' );
+				$message = __( 'An error has occurred.' );
 			} else {
 				$message = $result['message'];
 				unset( $result['message'] );
diff --git src/wp-admin/js/customize-controls.js src/wp-admin/js/customize-controls.js
index 785fc7f895..4e3da867a7 100644
--- src/wp-admin/js/customize-controls.js
+++ src/wp-admin/js/customize-controls.js
@@ -6836,7 +6836,7 @@
 
 		cheatin: function() {
 			$( document.body ).empty().addClass( 'cheatin' ).append(
-				'<h1>' + api.l10n.cheatin + '</h1>' +
+				'<h1>' + api.l10n.notAllowedHeading + '</h1>' +
 				'<p>' + api.l10n.notAllowed + '</p>'
 			);
 		},
diff --git src/wp-admin/media-upload.php src/wp-admin/media-upload.php
index 7b0bd53806..9ca47c65bd 100644
--- src/wp-admin/media-upload.php
+++ src/wp-admin/media-upload.php
@@ -35,7 +35,7 @@ $post_id = isset( $post_id ) ? (int) $post_id : 0;
 // Require an ID for the edit screen.
 if ( isset( $action ) && $action == 'edit' && ! $ID ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 		'<p>' . __( 'Invalid item ID.' ) . '</p>',
 		403
 	);
@@ -43,7 +43,7 @@ if ( isset( $action ) && $action == 'edit' && ! $ID ) {
 
 if ( ! empty( $_REQUEST['post_id'] ) && ! current_user_can( 'edit_post', $_REQUEST['post_id'] ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit this item.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/nav-menus.php src/wp-admin/nav-menus.php
index c73a05878a..7f19e8697b 100644
--- src/wp-admin/nav-menus.php
+++ src/wp-admin/nav-menus.php
@@ -22,7 +22,7 @@ if ( ! current_theme_supports( 'menus' ) && ! current_theme_supports( 'widgets'
 // Permissions Check
 if ( ! current_user_can( 'edit_theme_options' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit theme options on this site.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/network/site-users.php src/wp-admin/network/site-users.php
index d1a125b844..6adaefe6a7 100644
--- src/wp-admin/network/site-users.php
+++ src/wp-admin/network/site-users.php
@@ -159,7 +159,7 @@ if ( $action ) {
 					// If the user doesn't already belong to the blog, bail.
 					if ( ! is_user_member_of_blog( $user_id ) ) {
 						wp_die(
-							'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+							'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 							'<p>' . __( 'One of the selected users is not a member of this site.' ) . '</p>',
 							403
 						);
diff --git src/wp-admin/options.php src/wp-admin/options.php
index 5c13fd5e26..2149102280 100644
--- src/wp-admin/options.php
+++ src/wp-admin/options.php
@@ -46,7 +46,7 @@ if ( empty( $option_page ) ) {
 
 if ( ! current_user_can( $capability ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to manage these options.' ) . '</p>',
 		403
 	);
@@ -74,7 +74,7 @@ if ( ! empty( $_GET['adminhash'] ) ) {
 
 if ( is_multisite() && ! current_user_can( 'manage_network_options' ) && 'update' != $action ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to delete these items.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/post-new.php src/wp-admin/post-new.php
index 7c09650b85..737b626359 100644
--- src/wp-admin/post-new.php
+++ src/wp-admin/post-new.php
@@ -57,7 +57,7 @@ $editing = true;
 
 if ( ! current_user_can( $post_type_object->cap->edit_posts ) || ! current_user_can( $post_type_object->cap->create_posts ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to create posts as this user.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/press-this.php src/wp-admin/press-this.php
index 8f97728fec..7862fd8112 100644
--- src/wp-admin/press-this.php
+++ src/wp-admin/press-this.php
@@ -18,7 +18,7 @@ function wp_load_press_this() {
 	if ( ! current_user_can( 'edit_posts' ) || ! current_user_can( get_post_type_object( 'post' )->cap->create_posts ) ) {
 		wp_die(
 			__( 'Sorry, you are not allowed to create posts as this user.' ),
-			__( 'Cheatin&#8217; uh?' ),
+			__( 'You don&#8217;t have permission to do this.' ),
 			403
 		);
 	} elseif ( is_plugin_active( $plugin_file ) ) {
diff --git src/wp-admin/term.php src/wp-admin/term.php
index b8331828b4..d10121daa8 100644
--- src/wp-admin/term.php
+++ src/wp-admin/term.php
@@ -34,7 +34,7 @@ if ( ! in_array( $taxonomy, get_taxonomies( array( 'show_ui' => true ) ) ) ||
 	! current_user_can( 'edit_term', $tag->term_id ) ) {
 
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit this item.' ) . '</p>',
 		403
 	);
diff --git src/wp-admin/themes.php src/wp-admin/themes.php
index b399f92f67..6994e7fac1 100644
--- src/wp-admin/themes.php
+++ src/wp-admin/themes.php
@@ -11,7 +11,7 @@ require_once( dirname( __FILE__ ) . '/admin.php' );
 
 if ( ! current_user_can( 'switch_themes' ) && ! current_user_can( 'edit_theme_options' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit theme options on this site.' ) . '</p>',
 		403
 	);
@@ -24,7 +24,7 @@ if ( current_user_can( 'switch_themes' ) && isset( $_GET['action'] ) ) {
 
 		if ( ! $theme->exists() || ! $theme->is_allowed() ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 				'<p>' . __( 'The requested theme does not exist.' ) . '</p>',
 				403
 			);
@@ -39,7 +39,7 @@ if ( current_user_can( 'switch_themes' ) && isset( $_GET['action'] ) ) {
 
 		if ( ! current_user_can( 'delete_themes' ) ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 				'<p>' . __( 'Sorry, you are not allowed to delete this item.' ) . '</p>',
 				403
 			);
@@ -47,7 +47,7 @@ if ( current_user_can( 'switch_themes' ) && isset( $_GET['action'] ) ) {
 
 		if ( ! $theme->exists() ) {
 			wp_die(
-				'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+				'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 				'<p>' . __( 'The requested theme does not exist.' ) . '</p>',
 				403
 			);
diff --git src/wp-admin/user-new.php src/wp-admin/user-new.php
index 59e68dad76..f6ff3b7e58 100644
--- src/wp-admin/user-new.php
+++ src/wp-admin/user-new.php
@@ -12,14 +12,14 @@ require_once( dirname( __FILE__ ) . '/admin.php' );
 if ( is_multisite() ) {
 	if ( ! current_user_can( 'create_users' ) && ! current_user_can( 'promote_users' ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 			'<p>' . __( 'Sorry, you are not allowed to add users to this network.' ) . '</p>',
 			403
 		);
 	}
 } elseif ( ! current_user_can( 'create_users' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to create users.' ) . '</p>',
 		403
 	);
@@ -52,7 +52,7 @@ if ( isset( $_REQUEST['action'] ) && 'adduser' == $_REQUEST['action'] ) {
 
 	if ( ! current_user_can( 'promote_user', $user_details->ID ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 			'<p>' . __( 'Sorry, you are not allowed to add users to this network.' ) . '</p>',
 			403
 		);
@@ -136,7 +136,7 @@ Please click the following link to confirm the invite:
 
 	if ( ! current_user_can( 'create_users' ) ) {
 		wp_die(
-			'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+			'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 			'<p>' . __( 'Sorry, you are not allowed to create users.' ) . '</p>',
 			403
 		);
diff --git src/wp-admin/users.php src/wp-admin/users.php
index ac47c392c4..7d5a82571e 100644
--- src/wp-admin/users.php
+++ src/wp-admin/users.php
@@ -12,7 +12,7 @@ require_once( dirname( __FILE__ ) . '/admin.php' );
 
 if ( ! current_user_can( 'list_users' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to list users.' ) . '</p>',
 		403
 	);
@@ -141,7 +141,7 @@ switch ( $wp_list_table->current_action() ) {
 			// If the user doesn't already belong to the blog, bail.
 			if ( is_multisite() && ! is_user_member_of_blog( $id ) ) {
 				wp_die(
-					'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+					'<h1>' . __( 'An error has occurred.' ) . '</h1>' .
 					'<p>' . __( 'One of the selected users is not a member of this site.' ) . '</p>',
 					403
 				);
diff --git src/wp-admin/widgets.php src/wp-admin/widgets.php
index 533767023a..08f5baaafc 100644
--- src/wp-admin/widgets.php
+++ src/wp-admin/widgets.php
@@ -14,7 +14,7 @@ require_once( ABSPATH . 'wp-admin/includes/widgets.php' );
 
 if ( ! current_user_can( 'edit_theme_options' ) ) {
 	wp_die(
-		'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+		'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 		'<p>' . __( 'Sorry, you are not allowed to edit theme options on this site.' ) . '</p>',
 		403
 	);
diff --git src/wp-includes/class-wp-customize-manager.php src/wp-includes/class-wp-customize-manager.php
index 8da075634e..6d793d15db 100644
--- src/wp-includes/class-wp-customize-manager.php
+++ src/wp-includes/class-wp-customize-manager.php
@@ -447,7 +447,7 @@ final class WP_Customize_Manager {
 		}
 
 		if ( ! $message ) {
-			$message = __( 'Cheatin&#8217; uh?' );
+			$message = __( 'An error has occurred.' );
 		}
 
 		if ( $this->messenger_channel ) {
@@ -512,7 +512,7 @@ final class WP_Customize_Manager {
 				auth_redirect();
 			} else {
 				wp_die(
-					'<h1>' . __( 'Cheatin&#8217; uh?' ) . '</h1>' .
+					'<h1>' . __( 'You don&#8217;t have permission to do this.' ) . '</h1>' .
 					'<p>' . __( 'Sorry, you are not allowed to customize this site.' ) . '</p>',
 					403
 				);
diff --git src/wp-includes/class-wp-xmlrpc-server.php src/wp-includes/class-wp-xmlrpc-server.php
index c6e6cd8002..3552ac1a95 100644
--- src/wp-includes/class-wp-xmlrpc-server.php
+++ src/wp-includes/class-wp-xmlrpc-server.php
@@ -3879,7 +3879,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		}
 
 		if ( ! $comment_ID ) {
-			return new IXR_Error( 403, __( 'An unidentified error has occurred.' ) );
+			return new IXR_Error( 403, __( 'An error has occurred.' ) );
 		}
 
 		/**
diff --git src/wp-includes/functions.php src/wp-includes/functions.php
index ec5a3d26ce..89770f3cb5 100644
--- src/wp-includes/functions.php
+++ src/wp-includes/functions.php
@@ -2718,7 +2718,7 @@ function wp_nonce_ays( $action ) {
 			wp_logout_url( $redirect_to )
 		);
 	} else {
-		$html = __( 'Are you sure you want to do this?' );
+		$html = __( 'The link you followed no longer exists.' );
 		if ( wp_get_referer() ) {
 			$html .= '</p><p>';
 			$html .= sprintf(
@@ -2729,7 +2729,7 @@ function wp_nonce_ays( $action ) {
 		}
 	}
 
-	wp_die( $html, __( 'WordPress Failure Notice' ), 403 );
+	wp_die( $html, __( 'An error has occurred.' ), 403 );
 }
 
 /**
diff --git src/wp-includes/js/wp-ajax-response.js src/wp-includes/js/wp-ajax-response.js
index 50c66525af..b54eb0354e 100644
--- src/wp-includes/js/wp-ajax-response.js
+++ src/wp-includes/js/wp-ajax-response.js
@@ -56,7 +56,7 @@ var wpAjax = jQuery.extend( {
 		selector = jQuery( selector );
 		return !wpAjax.invalidateForm( selector.find('.form-required').filter( function() { return jQuery('input:visible', this).val() === ''; } ) ).length;
 	}
-}, wpAjax || { noPerm: 'Sorry, you are not allowed to do that.', broken: 'An unidentified error has occurred.' } );
+}, wpAjax || { noPerm: 'Sorry, you are not allowed to do that.', broken: 'An error has occurred.' } );
 
 // Basic form validation
 jQuery(document).ready( function($){
diff --git src/wp-includes/script-loader.php src/wp-includes/script-loader.php
index e26a0a99bf..79d2b7c763 100644
--- src/wp-includes/script-loader.php
+++ src/wp-includes/script-loader.php
@@ -137,7 +137,7 @@ function wp_default_scripts( &$scripts ) {
 	did_action( 'init' ) && $scripts->localize(
 		'wp-ajax-response', 'wpAjax', array(
 			'noPerm' => __( 'Sorry, you are not allowed to do that.' ),
-			'broken' => __( 'An unidentified error has occurred.' ),
+			'broken' => __( 'An error has occurred.' ),
 		)
 	);
 
@@ -605,7 +605,8 @@ function wp_default_scripts( &$scripts ) {
 			'close'                   => __( 'Close' ),
 			'action'                  => __( 'Action' ),
 			'discardChanges'          => __( 'Discard changes' ),
-			'cheatin'                 => __( 'Cheatin&#8217; uh?' ),
+			'cheatin'                 => __( 'An error has occurred.' ),
+			'notAllowedHeading'       => __( 'You don&#8217;t have permission to do this.' ),
 			'notAllowed'              => __( 'Sorry, you are not allowed to customize this site.' ),
 			'previewIframeTitle'      => __( 'Site Preview' ),
 			'loginIframeTitle'        => __( 'Session expired' ),
@@ -688,7 +689,7 @@ function wp_default_scripts( &$scripts ) {
 		did_action( 'init' ) && $scripts->localize(
 			'admin-tags', 'tagsl10n', array(
 				'noPerm' => __( 'Sorry, you are not allowed to do that.' ),
-				'broken' => __( 'An unidentified error has occurred.' ),
+				'broken' => __( 'An error has occurred.' ),
 			)
 		);
 
@@ -917,7 +918,7 @@ function wp_default_scripts( &$scripts ) {
 					'activateImporter'         => __( 'Run Importer' ),
 					/* translators: %s: Importer name */
 					'activateImporterLabel'    => __( 'Run %s' ),
-					'unknownError'             => __( 'An unidentified error has occurred.' ),
+					'unknownError'             => __( 'An error has occurred.' ),
 					'connectionError'          => __( 'Connection lost or the server is busy. Please try again later.' ),
 					'nonceError'               => __( 'An error has occurred. Please reload the page and try again.' ),
 					'pluginsFound'             => __( 'Number of plugins found: %d' ),
