You've indicated an error occurring that may be related to "Merge Module Holder Object 1". It is implied you are using Merge Modules in a pure InstallScript project. I suggest you enable Windows Installer logging using the Registry. Merge Module Objects are MSI based installs that are included with your pure InstallScript release. You can expect a Windows Installer log in the temp directory related to this matter. Properly back up your Registry and use caution when modifying the Registry. Reference: How to enable Windows Installer logging When the error occurs at runtime go to the user's temp directory and investigate what the Windows Installer log indicates. From the Start Menu tab (or Windows Key), click Run. Enter %temp% to examine contents of the user's temp directory. ... View more