As AppUp becomes more popular, many developers are publishing several apps at a time. However, to save time and resources, some developers are simply cloning a single MSI and then swapping out key files. Though this may appear to work, in actuality this shortcut will fail validation. Let me describe the scenario below. We begin with two apps I have as follows: App 1: Norman Chou - Hello App 2: Norman Chou – World Both apps pass validation and both apps are able to launch flawlessly from the store. In fact, it passes all the validation guidelines. Everything about each app independently works perfectly. However, if the apps are installed on the same device at the same time, one of the apps will fail to install. If App 1 is installed first, then App 2 will fail. Vice versa will fail as well. What appears to be happening is that the developer used the same MSI project of App 1 to make App 2 MSI. They have essentially cloned App 1 MSI. The developer is simply swapping out a few files like *exe, dll, resources, etc and then compiling the same MSI project from App 1. As a result, the MSI of both App 1 and App 2 has the same ID. This ID is different than that app GUID. Therefore when I try to install App 2 after App 1 is already on my device, the OS won’t install. The OS thinks the app is already there on the device since App 1 MSI ID is already in the registry. Check out this link to see how to fix the problem. http://appdeveloper.intel.com/en-us/article/one-my-apps-installs-other-wont
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