diff --git a/src/Utility/TrackingHelper.php b/src/Utility/TrackingHelper.php
index 93512eca..0ea0cbca 100644
--- a/src/Utility/TrackingHelper.php
+++ b/src/Utility/TrackingHelper.php
@@ -115,7 +115,7 @@ class TrackingHelper implements TrackingHelperInterface {
       // we actually need it.
       $map = NULL;
       foreach ($index->getDatasources() as $datasource_id => $datasource) {
-        if (!$datasource->canContainEntityReferences()) {
+        if (!$datasource || !$datasource->canContainEntityReferences()) {
           continue;
         }