Update group policy installed software without requiring a log off

You're seeing the dreaded scourge of asynchronous policy processing. It's not a "feature" (and was default-off in Windows 2000 but default-on in Windows XP and above) and causes exactly what you're seeing-- non-deterministic behaviour with processing some types of GPO settings.

In a GPO that applies to that computer, add the following setting:

• Computer Settings
  • Administrative Templates
    • System
      • Logon
        • Always wait for the network at computer startup and logon - Enabled

After you set that (and allow the GPO to replicate if you're in a multi-DC environment), do a "gpupdate /force /boot" on the subject PC. It will reboot and you should see the software installation occur.

The "Always wait for the network at computer startup and logon" slightly slows down the startup and logon because all GPO extensions are allowed to process, but the upside is that all GPO extensions are allowed to process.

I've had the desire to do something similiar and have done some reserach on the topic in the past.

There's no exposed API that I've been able to find to do what the Group Policy Editor is doing to create those application advertisment script (.aas) files and the corresponding records in AD. The PowerShell Group Policy API lets you configure registry-based settings, but not settings for other Group Policy Extensions.

There is now a reference to the Group Policy Software Installation Protocol Extension (thanks EU anti-trust settlement!) and I suppose you could try and roll engine to perform assignments yourself. The LDAP transactions necessary to perform the addition of the package and the format of the .aas files are in there. It looks a bit daunting (though fun)...

Frankly, your attention to detail re: deployment testing is to be commended. I wish you were writing software that my Customers use. The fact that you're using Windows Installer alone puts you ahead of the pack. That you know about Group Policy software deployment and are actually testing it makes me giddy! I wish some measurable fraction of developers cared as much as it's clear that you do.