Another transaction by user ... is already in progress for this app and major version.

Gotta love it when your app deployment tells you there was on error on your last attempt to deploy... 24 hours ago. WHAT!? Thanks for the heads up Google.

Recently got hit with "Another transaction by user ... is already in progress for this app and major version." during what I thought was going to be a quick update.

Thanks to John Ballinger for posting instructions.

1. Start -> Run -> cmd
2. cd into your application directory. For me, this is cd /Sites/appengine_myapp
3. appcfg.py --no_cookies --email=YOUR_EMAIL_HERE@gmail.com --passin rollback ./
4. You should be prompted for your password.

Nice.