OpenProcMon

OpenProcMon is a free, open-source Windows utility for capturing and examining low-level system activity. It best serves Windows developers, troubleshooters, and analysts who need detailed event traces, Process Monitor log compatibility, or programmable capture workflows. Its main trade-off is operational: live collection needs Administrator access on 64-bit Windows, while saved-log analysis is less demanding.

Overview

OpenProcMon combines real-time monitoring with inspection of existing Sysinternals Process Monitor logs. It covers process, file-system, registry, and network events, then lets you filter or highlight them by process name, PID, operation, path, result, or category. Those controls are valuable when a broad trace contains too much noise, especially during investigation of one process or operation.

The graphical interface adds a process tree, activity summaries, and call-stack views with module resolution for every frame. It reads and writes .PML files, including logs produced by the original Process Monitor, so a team can review or exchange captures without converting them first. The MIT license also makes the project suitable as a base for custom tooling, although its Rust rewrite remains under active development.

Key features

Capture and investigation

Live capture spans four major activity classes, giving analysts a broad view of what a process is doing across the system. Because collection loads a kernel driver, OpenProcMon must run as Administrator for that task. Opening and analyzing an existing .PML file requires no elevation, which is useful when you have a supplied trace but cannot obtain administrator rights on the review machine.

Developer and AI tooling

The Rust SDK can connect to the driver, choose which activity to monitor, apply filters, and consume parsed events in code. That makes it more than a standalone viewer: developers can build capture or analysis pipelines around its event stream. The procmon-cli MCP server exposes capture and analysis operations to AI agents over standard input/output, and MCP guides cover Claude Code, Claude Desktop, OpenAI Codex CLI, Cursor, Windsurf, Cline, and Continue. Capture tools can export filtered results as PML, CSV, or XML, giving automated workflows practical hand-off formats.

Pricing

There are no paid tiers, seat charges, trial terms, or renewal commitments. The cost advantage is straightforward, but the free plan does not remove the platform and privilege requirements: 32-bit Windows and 32-bit .PML files are outside its scope.

Platforms

OpenProcMon supports Windows, specifically 64-bit installations. The v0.5.0 Windows x64 ZIP bundles the GUI, CLI/MCP server, console example, skill, and MCP setup guides. It does not support 32-bit Windows or 32-bit .PML files.

Who it's for

Choose OpenProcMon if you need granular Windows event capture, call-stack-oriented investigation, or compatibility with existing Process Monitor logs. It is particularly well matched to developers building EDR-style tooling, analysts automating capture through an SDK, and teams adding AI-assisted investigation through MCP. It is a poor fit for 32-bit systems, and live collection is inconvenient where administrator elevation is unavailable.

Pros and cons

Pros

• Deep event coverage: process, file-system, registry, and network monitoring supports focused troubleshooting.
• Precise investigation tools: filters, highlighting, process trees, summaries, and resolved call stacks help turn noisy traces into usable evidence.
• Strong interoperability: reading and writing Sysinternals .PML files preserves existing capture workflows.
• Automation ready: the Rust SDK, MCP server, and PML/CSV/XML exports support scripted and AI-assisted analysis.
• No licensing bill: the MIT-licensed project is free to use.

Cons

• 64-bit Windows only: it cannot serve 32-bit Windows installations or 32-bit PML archives.
• Elevation for collection: live capture requires Administrator privileges and a kernel driver.
• Active rewrite: the Rust rewrite is still under active development, so buyers seeking a settled product may prefer a more established option.

Alternatives

Process Monitoring Software is the broader category to browse when you want to compare multiple monitoring tools. Glances is a free, open-source system monitor spanning Android, API, Linux, macOS, self-hosted, web, and Windows, with optional features needing extra dependencies. PM2 is the better choice for process management and a real-time web interface, with a free Runtime plan and a paid Plus tier at $79 a month.

bottom (btm) is a free resource monitor for Linux, macOS, and Windows. btop is a free resource monitor for Linux and macOS, while htop offers freely available binaries and source code on Linux and macOS. Monit suits Linux, macOS, and self-hosted monitoring under the AGPL. Process Lasso is a Windows freemium option with paid single-PC subscriptions when you want a commercial process-management product. runit is a free Linux, macOS, and self-hosted service supervisor without stated commercial limits.

Verdict

OpenProcMon is a strong choice for 64-bit Windows users who need detailed, filterable event traces, .PML interoperability, and developer or AI automation at no cost. Choose it when capture depth and programmable analysis matter more than a polished, platform-independent monitor. Look elsewhere if you need 32-bit support or cannot grant Administrator privileges for live collection.