I've done several release of my program, each time the new installer just overwrites the files as it should. However, I just updated to version 2010, and now when I create a new installer it creates a new instance of the installation instead of overwriting it. So in add/remove programs the installation shows up twice. The upgrade code is the exact same and nothing else about the project has changed. What could be happening?
I tried to create an upgrade path, which did work in that it didn't have two instances of the installer in add/remove programs. But it removed a DLL that was in the old version and the new version, I don't know why it would do this!??
if you are using dynamic file linking at build time you are likely getting a component GUID mismatch that is causing the problem of removing the dll. You can resolve this by making sure the component GUIDS match or if you are doing dynamic linking you can do this by changing your major upgrade behavior to do a complete uninstall before installing.
I saw this behavior when I dropped a file and then later had to add the file back, even though the filename was the same it was considered to be a different file because the component GUID had changed.
this is assuming you are using the Basic MSI project type. might be slightly different for other project types.
in the Upgrades view select the header "Upgrade Windows Installer Setup" and on the right side you should see two sections. In the section labeled "Major upgrade Settings" choose the "Completely uninstall old setup before installing new setup" option.
