diff --git a/src/extension-support/extension-manager.js b/src/extension-support/extension-manager.js
index 38378fdb..cf1f32db 100644
--- a/src/extension-support/extension-manager.js
+++ b/src/extension-support/extension-manager.js
@@ -280,7 +280,7 @@ class ExtensionManager {
                     dispatch.call('runtime', '_refreshExtensionPrimitives', info);
                 })
                 .catch(e => {
-                    log.error(`Failed to refresh built-in extension primitives: ${JSON.stringify(e)}`);
+                    log.error(`Failed to refresh built-in extension primitives: ${e}`);
                 })
         );
         return Promise.all(allPromises);