I have some problem help me

I get this error right after the update. in windows 10
ionic 2.1.0 ->> 2.1.12

Your system information:

ordova CLI: 6.4.0
Ionic CLI Version: 2.1.12
Ionic App Lib Version: 2.1.7
ios-deploy version: Not installed
ios-sim version: Not installed
OS: Windows 10
Node Version: v6.9.1
Xcode version: Not installed

When I create a new project and run it, the default screen does not appear.

ionic start new blank --v2
cd new
ionic start

I have tried many times

new/www/build/polyfills.js seems to be a problem.

When I change the file to the one in the previous project, it works fine, but when I run it again, a blank screen appears again.

I think there is a problem with the build configuration. But I did not touch anything and just used the built-in template.

help me plz