diff --git a/packages/fether-react/src/RequireHealthOverlay/RequireHealthOverlay.js b/packages/fether-react/src/RequireHealthOverlay/RequireHealthOverlay.js
index 3c1ac3dd4..f05bf1d2e 100644
--- a/packages/fether-react/src/RequireHealthOverlay/RequireHealthOverlay.js
+++ b/packages/fether-react/src/RequireHealthOverlay/RequireHealthOverlay.js
@@ -19,6 +19,8 @@ function statusMatches (status, require) {
       );
     case 'sync':
       return status === STATUS.GOOD;
+    default:
+      throw new Error(`Status '${status}' must be one of 'connected|sync'.`);
   }
 }