diff --git a/index.js b/index.js
index f15e588..c463985 100644
--- a/index.js
+++ b/index.js
@@ -230,7 +230,7 @@ class Installer {
           }
         })
       })
-    }, {concurrency: 50, Promise: BB})
+    }, {concurrency: 1, Promise: BB})
   }
 
   updateFromField (dep, pkg) {