Coworker started getting the above message in the event log and as dialog during install. Argument [2] was File and argument [3] was a specific file. Error dialog read Product: (app name) -- The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2602. Package was a vendor-provided MSI that had been installed administratively, and then a patch (.msp) applied to the administrative install point. With some digging we ......