diff --git a/app/src/package-manager.es6 b/app/src/package-manager.es6
index 009b67431..6cbf4090e 100644
--- a/app/src/package-manager.es6
+++ b/app/src/package-manager.es6
@@ -168,7 +168,7 @@ export default class PackageManager {
       );
     }
 
-    if (!json.engines.mailspring) {
+    if (!json.engines || !json.engines.mailspring) {
       return callback(
         new Error(
           localized(