We are working on an update system for our software. The updater should in the background as a service, and when an update is available, downloads and installs it. We need the service to install the update since the msi requires elevation to run, but some of our clients will be restricted users.

The MSI is a WIX MSI and does a Major Upgrade when run. The problem is, the update does not seem to work when ran from our service. I can see msiexec run, and it returns successfully, but seems to make no changes to the system. The same command, when run from my user account works as expected.

Is there some caveat to running msiexec from a Local System service?

We are simply doing:

System.Diagnostics.Process.Start("msiexec.exe", arguments);