I experienced the following errors when attempting to upgrade Visual Studio 2010 Ultimate on my TFS application server (WS08 R2): The file '[path\file prefix].msi' is not a valid installation package for the product... The VS2010 repair and uninstall also failed for the same reasons In my case, the specific problem was with Silverlight, the TFS object model and Help Viewer 1.0 With excellent help from Microsoft support, I took the following steps to resovle the problems: Determine what VS 2010 RTM ......