Filemon

Process Monitor is a free tool from Windows Sysinternals, part of the Microsoft TechNet website. The tool monitors and displays in real-time all file system activity on a Microsoft Windows operating system. It combines two older tools, FileMon and RegMon and is used in system administration, computer forensics, and application debugging.

Process Monitor monitors and records all actions attempted against the Microsoft Windows Registry. Process Monitor can be used to detect failed attempts to read and write registry keys. It also allows for filtering on specific keys, processes, process IDs, and values. In addition it shows how applications use files and DLLs, detects some critical errors in system files and more.

RegMon and its sister application Filemon were primarily created by Mark Russinovich and Bryce Cogswell, employed by Nu-Mega Technologies and later SysInternals prior SysInternals being bought out by Microsoft in 2006.

The two tools were combined to create Process Monitor. Early versions of Process Monitor (up to version 2.8) ran on Windows 2000 SP4 with Update Rollup 1. The current version only runs on Windows Vista and above.

FileMon (from a concatenation of "File" and "Monitor") — was a free utility for 32/64-bit Microsoft Windows operating systems which provided users with a powerful tool to monitor and display file system activity.