Fixing the “Another user has already installed an unpackaged version” error with Windows 8 Metro applications

If you are developing Windows 8 Metro applications with Visual Studio 11 Beta, and you have created new user profiles (or deleted previous ones), you might have run into the following deployment error while building your Windows Runtime application in Visual Studio:

Error: Another user has already installed an unpackaged version of this application. The current user cannot replace this with a packaged version.

This is a development time-error, and could be fixed in two ways: first, you could log in again with the original account you used (if that is still available), or you could simply go a change your Metro application's GUID in the package manifest file "Package.appxmanifest". This is an XML based file (to which Visual Studio provides a user interface for editing), and it starts with the Package element. Beneath it, you will find an Identity element, which contains the Name attribute. Change the value of this GUID – a single digit edit will do – and your application will successfully build and launch.

I first encountered this error when I had just installed Windows 8 Consumer Preview, and then joined the computer to a domain. I had started authoring an application with the user account created when I logged in with the Microsoft Live Id ("Microsoft Account") and then after the domain join, continued development with my domain user account.

Hope this helps!