diff --git a/lib/install/inflate-shrinkwrap.js b/lib/install/inflate-shrinkwrap.js
index 395cc11191309..c4b9aaadfa632 100644
--- a/lib/install/inflate-shrinkwrap.js
+++ b/lib/install/inflate-shrinkwrap.js
@@ -74,7 +74,9 @@ function quotemeta (str) {
 }
 
 function tarballToVersion (name, tb) {
-  const registry = quotemeta(npm.config.get('registry'))
+  var x = npm.config.get('registry')
+  if (x === null) x = ''
+  const registry = quotemeta(x)
     .replace(/https?:/, 'https?:')
     .replace(/([^/])$/, '$1/')
   let matchRegTarball