Category: Tutorial

Modern Windows records a user’s default application separately from the older extension-to-ProgID mappings stored below Software\Classes. Both mechanisms still exist, but they serve different purposes and do not have the same priority. In short: a legacy mapping can register or provide a fallback handler, but it should not be treated…

A ProgID is the link between a Windows file type or protocol and the application that handles it. Understanding that link makes it much easier to inspect, troubleshoot, and deploy default associations. The essential distinction: registering a ProgID tells Windows that an application can handle a file type. Selecting that…