Running msiexec from a service (Local System account)

Question

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:

string arguments = "/i /quiet /lv*x " + pathToLogFile;   
System.Diagnostics.Process.Start("msiexec.exe", arguments);

Answer 1

If your service is a windows service then do a follow steps :

1.Open properties of your service in Services console.

2.Go to Log On tab

3.Set there an account that has rights to update the system (yours or specially created for this purpose)

1. Restart the service

In this case, the service will be runned with proper rights and can do updates.

Answer 2

Please do not design your software to install yet another software update service. It is simply inefficient and wrong, as it slows down the boot time and eats system resources for a process that is mostly doing nothing.

Create a small "application launcher" executable instead, which has the option of checking for updates before running the application. This also allows you to give users the option to "upgrade before launching" or "upgrade when exiting" should you so desire.

If you absolutely must have a Windows service then be sure to have it start delayed on boot and to shut itself down after checking for updates. The client process can start the service when it is launched.

As for your specific problem, most likely the update is being installed under a different user account. Starting the process with the users credentials should resolve the problem.

Answer 3

I also had the same task described above and I found that if program was installed for ALL users, running msiexec would work from Service which is running under SYSTEM account. So to make this work, you will have to install for ALL users. In my case, I specified msxexec command as follows when the program is first installed.

msiexec /i setup.msi ALLUSERS="1"

Once this is done, you can just upgrade the program from Service without any issue.

Answer 4

You may need to use the REINSTALLMODE parameter that allows you to control the upgrade. If they are not provided, the installation may silently fail to upgrade your app (or at least that's what I've found, though I'm still a little unsure whether the same behaviour applies under System.Diagnostics.Process.Start):

msiexec.exe /i /quiet yourinstaller.msi REINSTALL=All REINSTALLMODE=vomus

See here for more info on the various flags that you can pass to msiexec.exe.