by Stian

WP7: Application launch failed

When you try to deploy your WP7 applications from Visual Studio to your phone, you might get the message: “Application launch failed. Ensure that the device screen is unlocked and device is developer unlocked. For details on developer unlock, visit

The link you get is only a link to, which does not actually help you solve the problem.

Very often we find that the reason for this error message is the device screen is unlocked, but it is also necessary to register your device on your developer account to be able to deploy. You already have the tools you need on your computer, just follow these instructions:

Developer Phone Registration

  1. Go to “All Programs” on your start menu and find “Windows Phone Developer Tools
  2. Start “Windows Phone Developer Registration
  3. Fill inn Windows Live ID and password.
  4. Click “Register