diff --git a/src/main/java/com/github/tomakehurst/wiremock/standalone/JsonFileMappingsSource.java b/src/main/java/com/github/tomakehurst/wiremock/standalone/JsonFileMappingsSource.java
index b53484cbcb..a9d0b44d6b 100644
--- a/src/main/java/com/github/tomakehurst/wiremock/standalone/JsonFileMappingsSource.java
+++ b/src/main/java/com/github/tomakehurst/wiremock/standalone/JsonFileMappingsSource.java
@@ -149,9 +149,10 @@ private boolean hasFolderDefinition(final StubMapping mapping) {
     if (metadata == null) {
       return false;
     }
-    return metadata.getMap(WIREMOCK_GUI_KEY) != null
-        && metadata.getMap(WIREMOCK_GUI_KEY).get(DIR_KEY) != null
-        && metadata.getMap(WIREMOCK_GUI_KEY).get(DIR_KEY) instanceof String;
+
+    return metadata.containsKey(WIREMOCK_GUI_KEY)
+      && metadata.getMap(WIREMOCK_GUI_KEY).get(DIR_KEY) != null
+      && metadata.getMap(WIREMOCK_GUI_KEY).get(DIR_KEY) instanceof String;
   }
 
   private String getFolderDefinition(final StubMapping mapping) {