Index: src/wp-admin/install.php
===================================================================
--- src/wp-admin/install.php	(revision 32685)
+++ src/wp-admin/install.php	(working copy)
@@ -193,6 +193,12 @@
 	die( '<h1>' . __( 'Configuration Error' ) . '</h1><p>' . __( 'Your <code>wp-config.php</code> file has an empty database table prefix, which is not supported.' ) . '</p></body></html>' );
 }
 
+// Set error message if DO_NOT_UPGRADE_GLOBAL_TABLES isn't set as it will break install.
+if ( defined( 'DO_NOT_UPGRADE_GLOBAL_TABLES' ) && true === DO_NOT_UPGRADE_GLOBAL_TABLES ) {
+	display_header();
+	die( '<h1>' . __( 'Configuration Error' ) . '</h1><p>' . __( 'The constant DO_NOT_UPGRADE_GLOBAL_TABLES cannot be defined when creating a new site.' ) . '</p></body></html>' );
+}
+
 /**
  * @global string    $wp_local_package
  * @global WP_Locale $wp_locale