We received a vendor MSI in which we created a response transform. I need to add a System Environment Variable to set the licensing server, after creating it with "On Install" = Set and "Placement" = Leave when installing the MSI / MST the system variable is not being set. I have also changed the Component that is associated with the environment variable still with no luck.
Environment variables are tricky. Sometimes, the only way to truly get them reflected across the system is a system restart (microsoft says this in so many words).
If it's not updating successfully, you could broadcast a WM_SETTINGCHANGE message in script like some Microsoft KB's mention, but last I looked into this it could cause a hang in the script on UAC enabled machines. But of course, it depends on exactly what's going on with your install.
I'd probably start with the sanity check to make sure the MSI log mentions it's installing the variable during the WriteEnvironmentStrings action. It's possible the vendor MSI doesn't have this action sequenced! Or possible that something else is going on (maybe the variable is associated with a component that's not being installed). Once you establish in the log that it's getting installed OK, then worry about whether you need to reboot the machine or similar.
