diff --git a/lib/google/api_client/auth/installed_app.rb b/lib/google/api_client/auth/installed_app.rb
index 2edf36332..e6bd31666 100644
--- a/lib/google/api_client/auth/installed_app.rb
+++ b/lib/google/api_client/auth/installed_app.rb
@@ -92,9 +92,10 @@ module Google
           :Logger => WEBrick::Log.new(STDOUT, 0),
           :AccessLog => []
         )
-        trap("INT") { server.shutdown }
-        
-        server.mount_proc '/' do |req, res|
+        begin
+          trap("INT") { server.shutdown }
+
+          server.mount_proc '/' do |req, res|
             auth.code = req.query['code']
             if auth.code
               auth.fetch_access_token!
@@ -102,10 +103,13 @@ module Google
             res.status = WEBrick::HTTPStatus::RC_ACCEPTED
             res.body = RESPONSE_BODY
             server.stop
-        end
+          end
 
-        Launchy.open(auth.authorization_uri.to_s)
-        server.start
+          Launchy.open(auth.authorization_uri.to_s)
+          server.start
+        ensure
+          server.shutdown
+        end
         if @authorization.access_token
           if storage.respond_to?(:write_credentials)
             storage.write_credentials(@authorization)