If your custom software requires the primary interop assemblies (PIAs) to talk to Office, you need the official redists. Navigate to Microsoft's developer portal.

Microsoft Office Tools Common v9.0 is a software package that provides a set of common components and libraries used by various Microsoft Office applications. It is designed to enhance the functionality and performance of Office applications, ensuring a seamless user experience. The package includes several tools, such as the Microsoft Office Click-to-Run, Microsoft Office Configuration Manager, and Microsoft Office Online Configuration Tool, among others.

Allow the tool to repair the corrupted registry identifiers. Security Warning Regarding Third-Party Download Sites

If you are a software developer trying to build or debug a legacy environment on a modern machine, you can source the library using the Visual Studio Installer workflow: Open the tool on your desktop. Select your active installation and click Modify .

If the software is already installed but throwing errors, use the built-in repair tool to fix missing DLLs or registry paths:

What (e.g., 2010, 2013, 2016) is installed?

Scroll through the list to find your installation. Right-click the application and select Change .

Understanding Microsoft.Office.Tools.Common.v9.0: Purpose, Safe Sourcing, and Setup

Download and install or reinstall Office 2021, Office 2019, or Office 2016