diff --git a/plugin.php b/plugin.php
index 19d2e2aab..a660ba493 100644
--- a/plugin.php
+++ b/plugin.php
@@ -26,7 +26,8 @@ function stackable_multiple_plugins_check() {
 	}
 }
 
-if ( defined('STACKABLE_FILE') && STACKABLE_FILE !== __FILE__ && ! isset( $GLOBALS['OTHER_STACKABLE_FILE'] ) ) {
+if ( defined('STACKABLE_FILE') && STACKABLE_FILE !== __FILE__ && ! isset( $GLOBALS['OTHER_STACKABLE_FILE'] ) &&
+	defined( 'STACKABLE_BUILD' ) && defined( 'STACKABLE_VERSION' ) ) {
 	// Get relative file path of the other Stackable version.
 	$GLOBALS['OTHER_STACKABLE_FILE'] = plugin_basename( STACKABLE_FILE );