Summary

Locating MSI Upgrade Codes in the Windows Registry

Synopsis

When troubleshooting MSI installation issues, it may be beneficial to locate the installers Upgrade code within the Registry.

This article will discuss where this information is located.

Discussion

When an MSI is installed it will store its Upgrade Code in the Windows Registry in the following location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UpgradeCodes\

Be aware that Microsoft use a simple encryption when storing upgrade codes meaning you have to do the following:

e.g. for {016BACC2-4BD7-4137-BA71-756536C0DC40}

1. Reverse first 8 characters 2CCAB610
2. Reverse next 4 characters 7DB4
3. Reverse next 4 characters 7314
4. Reverse next 2 characters AB
5. Reverse next 2 characters 17
6. Reverse next 2 characters 57
7. Reverse next 2 characters 56
8. Reverse next 2 characters 63
9. Reverse next 2 characters 0C
10. Reverse next 2 characters CD
11. Reverse next 2 characters 04

thus {016BACC2-4BD7-4137-BA71-756536C0DC40}
becomes 2CCAB6107DB47314AB175756630CCD04

The value associated to the upgrade code is the ProductCode of the installer. This however is also encrypted meaning to find its true value it will need to be reversed using the process above.