I am often asked why file changes don’t appear in the handy Windows Installer tool, Orca. When people open an .msp patch package in Orca, they will likely see something like the following:

As described in What’s in a Patch, a patch package contains transforms and, optionally, tables. Currently, Windows Installer-supported tables include the MsiPatchMetadata and MsiPatchSequence tables. In order to view the changes a patch would make to a product, you need to open up the target .msi installer package in Orca first.

After you’ve opened the .msi package in Orca, either click the Transform -> View Patch menu item or drag-and-drop an .msp package into the window. If that .msp is a small update that targets a latter minor upgrade, apply that minor upgrade using one of the methods described previously first. Once the .msp is applied, you’ll see all changes to the product in green as you can see below: