XP users may receive an error when attempting to launch Age of Empires II: HD Edition.
Hidden Path has identified the issue and is working with Valve to ensure proper integration with Steam technology.
We apologize for the inconvenience and will provide updates in this announcement.
*Update 4/8 - 12PM -7GMT* We're currently testing the resolution with steam tech integration.
*Update 4/8 4PM -7GMT* The XP test build is currently in the 'player eval' branch. You can access it now from the beta tab. The password is (without quotes) the lowercase letter "a" - it will be integrated into the main game within the next day or two.