Hello. I'm trying to get the serial number from the registry *during an update* by using a Custom Behavior - registry search (call it PID_PROPERTY). I have found the serial number by doing a manual search in the registry, it is located at HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products\[GUID]\InstallProperties\, under the value ProductID.
If I set my PID_PROPERTY to hard code the GUID that's in the registry, it finds it no problem. But I can't do this because it seems like the GUID changes from version to version. And the odd thing is, the GUID that's currently showing in the registry, I have no idea where it has come from. It doesn't match our upgrade code or our product code... Any idea on if there's a property that stores this value?