Answer

There have been occasional reports that a patch will not update the patched version of an installation, but is able to patch the full version.

A patch (.msp) sometimes cannot recognize an .msi installation that has a previous patch applied. Removing previous applied patches associated with the .msi file prevents inconsistencies from occurring when applying a patch and allows the patch to work successfully.

1. On the dialog Specify Upgrade Version in the Patch Creation wizard, click the Advanced button. The Advance Upgrade Version Details dialog appears.
2. Click on Browse in the Previous Patch GUIDs to replace field to select the location of the old patches. This option unregisters the old patch and removes it prior to running the new patch. To remove multiple patches, list each product code with no delimiters.

The patch (.msp) removes the any specified versioned patches, and then the new patch (.msp file) is applied. Removing previous versions of patches prevents inconsistencies when applying multiple patches.