In the eyes of the Windows Installer, 4.2 was 4.1. But because the file versions were different, the installer didn't know whether to perform a "Small Update," a "Minor Upgrade," or a "Major Upgrade." It simply panicked and locked the doors.
| Identifier | Scope | When it changes | Used for | | :--- | :--- | :--- | :--- | | | Per-version | Every major or minor release (if new install logic is needed) | Identifying the installed instance of a product. | | Package Code | Per-build | Every single build (always) | Uniquely identifying the .MSI file itself. Do not manually change this. | | Upgrade Code | Per-product | Never (over the lifetime of the product) | Linking all versions of the same product for major upgrades. | installshield product code
He navigated to the . There it was—the Product Code , a 38-character GUID: E4B2... . This unique string was the software’s social security number. It told Windows, "I am this specific version of this specific thing." In the eyes of the Windows Installer, 4
While it looks like a random string of characters, the Product Code is the anchor of your installation. It ensures that Windows knows exactly what is on the machine, how to fix it, and how to replace it when a better version comes along. during your build process? | | Package Code | Per-build | Every
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ProductCode