diff --git a/buildutils/src/local-repository.ts b/buildutils/src/local-repository.ts
index 14b9094756ef..946f9d9abfff 100644
--- a/buildutils/src/local-repository.ts
+++ b/buildutils/src/local-repository.ts
@@ -132,10 +132,30 @@ packages:
   const pass = 'bar';
   const email = 'foo@bar.com';
   console.log('Logging in');
-  child_process.execSync(`npm login -e ${email} -r ${local_registry}`, {
-    input: `${user}\n${pass}\n${email}\n`
+  const loginPs = child_process.spawn(
+    'npm',
+    `login -e ${email} -r ${local_registry}`.split(' ')
+  );
+
+  const loggedIn = new Promise<void>(accept => {
+    loginPs.stdout.on('data', (chunk: string) => {
+      const data = Buffer.from(chunk, 'utf-8').toString();
+      console.log('debug:', data);
+      if (data.indexOf('Logged in as') !== -1) {
+        console.log('debug: matched');
+        loginPs.stdin.end();
+        accept();
+      }
+    });
   });
 
+  loginPs.stdin.write(user + '\n');
+  loginPs.stdin.write(pass + '\n');
+  loginPs.stdin.write(email + '\n');
+  console.log('debug: written, awaiting');
+  await loggedIn;
+  loginPs.kill();
+
   console.log('Running in', out_dir);
   ps.exit(0);
 }