diff --git a/wp-admin/includes/class-wp-automatic-updater.php b/wp-admin/includes/class-wp-automatic-updater.php
index 7ba6b71b52..a0405fd0a3 100644
--- a/wp-admin/includes/class-wp-automatic-updater.php
+++ b/wp-admin/includes/class-wp-automatic-updater.php
@@ -1236,9 +1236,15 @@ class WP_Automatic_Updater {
 		$body[] = __( 'https://wordpress.org/support/forums/' );
 		$body[] = "\n" . __( 'The WordPress Team' );
 
+		if ( '' !== get_option( 'blogname' ) ) {
+			$site_title = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
+		} else {
+			$site_title = parse_url( home_url(), PHP_URL_HOST );
+		}
+
 		$body    = implode( "\n", $body );
 		$to      = get_site_option( 'admin_email' );
-		$subject = sprintf( $subject, wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ) );
+		$subject = sprintf( $subject, $site_title );
 		$headers = '';
 
 		$email = compact( 'to', 'subject', 'body', 'headers' );
@@ -1347,7 +1353,11 @@ class WP_Automatic_Updater {
 			$body[] = '';
 		}
 
-		$site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
+		if ( '' !== get_bloginfo( 'name' ) ) {
+			$site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
+		} else {
+			$site_title = parse_url( home_url(), PHP_URL_HOST );
+		}
 
 		if ( $failures ) {
 			$body[] = trim(
diff --git a/wp-admin/includes/misc.php b/wp-admin/includes/misc.php
index aeeccc9b6f..3b4b6f3e47 100644
--- a/wp-admin/includes/misc.php
+++ b/wp-admin/includes/misc.php
@@ -1472,12 +1472,18 @@ All at ###SITENAME###
 	$content      = str_replace( '###SITENAME###', wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ), $content );
 	$content      = str_replace( '###SITEURL###', home_url(), $content );
 
+	if ( '' !== get_option( 'blogname' ) ) {
+		$site_title = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
+	} else {
+		$site_title = parse_url( home_url(), PHP_URL_HOST );
+	}
+
 	wp_mail(
 		$value,
 		sprintf(
 			/* translators: New admin email address notification email subject. %s: Site title. */
 			__( '[%s] New Admin Email Address' ),
-			wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES )
+			$site_title
 		),
 		$content
 	);
diff --git a/wp-admin/includes/user.php b/wp-admin/includes/user.php
index 6563859ef7..64b91fce19 100644
--- a/wp-admin/includes/user.php
+++ b/wp-admin/includes/user.php
@@ -578,6 +578,12 @@ function admin_created_user_email( $text ) {
 	$roles = get_editable_roles();
 	$role  = $roles[ $_REQUEST['role'] ];
 
+	if ( '' !== get_bloginfo( 'name' ) ) {
+		$site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
+	} else {
+		$site_title = parse_url( home_url(), PHP_URL_HOST );
+	}
+
 	return sprintf(
 		/* translators: 1: Site title, 2: Site URL, 3: User role. */
 		__(
@@ -590,7 +596,7 @@ this email. This invitation will expire in a few days.
 Please click the following link to activate your user account:
 %%s'
 		),
-		wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES ),
+		$site_title,
 		home_url(),
 		wp_specialchars_decode( translate_user_role( $role['name'] ) )
 	);
diff --git a/wp-admin/user-new.php b/wp-admin/user-new.php
index 220e0c53eb..4bc2d133cd 100644
--- a/wp-admin/user-new.php
+++ b/wp-admin/user-new.php
@@ -112,6 +112,12 @@ if ( isset( $_REQUEST['action'] ) && 'adduser' === $_REQUEST['action'] ) {
 
 			$switched_locale = switch_to_locale( get_user_locale( $user_details ) );
 
+			if ( '' !== get_option( 'blogname' ) ) {
+				$site_title = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
+			} else {
+				$site_title = parse_url( home_url(), PHP_URL_HOST );
+			}
+
 			/* translators: 1: Site title, 2: Site URL, 3: User role, 4: Activation URL. */
 			$message = __(
 				'Hi,
@@ -127,7 +133,7 @@ Please click the following link to confirm the invite:
 			$new_user_email['subject'] = sprintf(
 				/* translators: Joining confirmation notification email subject. %s: Site title. */
 				__( '[%s] Joining Confirmation' ),
-				wp_specialchars_decode( get_option( 'blogname' ) )
+				$site_title
 			);
 			$new_user_email['message'] = sprintf(
 				$message,
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f74b846764..cb0a65721c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0-alpha-53062';
+$wp_version = '6.0-alpha-53063';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.