Installing assemblies to GAC with Windows Installer

Question

I am creating a Windwos Installer project just for the use of installing our third party assemblies into the gac of the users computer. The problem i am running into, is when i make an update to the assemblie and increment it's version number, i get an error saying: "Another version of this product is already installed. Installation of this version cannot continue..." I would have figured that windows installer would update the local machine with the new assemblie. Am i doing something wrong?

Answer 1

It sounds to me like you're updating the version number of the assemblies, and you're updating the version number of the MSI package, but you're not changing the ProductCode.

If you change the ProductCode, you will enable a "Major Upgrade", and this error message will go away.

If you don't change the ProductCode, then you'll need to run a command-line like:

msiexec.exe -i mymsifile.msi REINSTALL=ALL REINSTALLMODE=vomus

This is known as a "Minor Upgrade".

See the MSDN articles on Minor Upgrade and Major Upgrade for clarification.