diff --git a/lib/content-services/search/search-query-builder.service.ts b/lib/content-services/search/search-query-builder.service.ts
index 4826e1262c..0c6294c4e0 100644
--- a/lib/content-services/search/search-query-builder.service.ts
+++ b/lib/content-services/search/search-query-builder.service.ts
@@ -61,7 +61,9 @@ export class SearchQueryBuilderService {
         this._userQuery = value ? `(${value})` : '';
     }
 
-    config: SearchConfiguration;
+    config: SearchConfiguration = {
+        categories: []
+    };
 
     // TODO: to be supported in future iterations
     ranges: { [id: string]: SearchRange } = {};