It is one of the great annoyances with Roaming Profiles and MSI-based installs, that if you reformat your PC, you can lose the link to your MSI package.  Here’s today’s example:
Missing MSI Source

I got the above dialog box when I tried to install the latest version of AWESync.  Not that it’s an AWESync caused problem, but the lack of the original AWESync 4.9.1 install file.

Now I could grovel around in the registry and manually fix the problem, or I could cheat and fix the problem quickly.

Let’s cheat; and use the Microsoft Windows Installer Cleanup Utility.

But do note the following from Microsoft:

“While the Windows Installer Cleanup utility resolved some installation problems, it sometimes damaged other components installed on the computer. Because of this, the tool has been removed from the Microsoft Download Center.”

We’re all adults here, and since we’re obtained a copy of MSICUU2.exe from elsewhere, let’s continue:

Windows Installer Clean Up

It’s as simple as selecting the package you want to “clean up”, and then clicking Remove.

Windows Installer Clean Up - Warning

Read the warning, and then click OK.

After a minute, the selected program MSI registry keys will be removed, and you’ll be able to install the MSI package you want.

More on Haack’s Troubleshooting Windows MSI Installers
Uninstall without the MSI file