MSI, (also known as the Microsoft Windows Installer), is the traditional way of installing Office via a local installation resource.By default, the latest version of Office which is included in Microsoft 365, and most one-time purchases of Office 2019 and Office 2016 products (such as Office Home & Business are installed by using Click-to-Run. Click-to-Run is a new way to install and update Office over the Internet and it works similarly to streaming video.Step 1 – Determine your installation typeīefore you begin the manual steps, determine your Office installation type so you can choose the correct way to uninstall it: Warning: Before you start, you need to know removing Office manually is a long, complex process and might require that you reinstall the operating system if certain steps are done incorrectly.