I am just in the process of creating my first 64-bit installer, and I am having problems. This is an existing 32-bit Basic MSI project, to which I am adding one or two 64-bit components. According to the articles I've read it should just be a case of setting the Template Summary to "x64;1033" and flagging the 64-bit components as 64-bit, which I have done and it has built successfully. However, when I come to try and install it on an x64 platform it extracts the MSI and then I just get the error message "This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package."
