How can I force a major upgrade to not switch to maintenance mode using the old installation package?

Question

I have an installer that I would like to use for a major upgrade. I have done the following:

• Increased the version number (from a.b.c to a.b.c+1)
• Changed the ProductCode
• Kept the same UpgradeCode
• Made the appropriate entry in the Upgrade table
• Changed the component ID of an existing component
• Changed the name of the installer package
• Changed the PackageCode

Basically I've done everything I can think of to force MSI to treat this as a major upgrade.

However, when I attempt to install this new package, the installer log says "Product registered: entering maintenance mode" and proceeds to try to find the old installer file (which fails, since the new installer is in a different folder than was used for the original installation, and wasn't even what I wanted to happen).

What am I missing? Why does the installer switch to maintenance mode right away rather than perform the major upgrade?

Thanks!

EDIT: Making this a part of the community wiki

Answer 1

As it turns out, this was due to a bug in the Wise Installer plug-in for Visual Studio. Apparently it gets confused and starts giving the same package code to all .msi packages it generates as a part of the build (regardless of the package code in the .wsi file).