CMTrace Open

A free, open-source log viewer and Windows troubleshooting tool. Drop in a log file and start reading — no install wizards, no prerequisites, no license keys.

Built as a modern replacement for Microsoft's CMTrace.exe with added Intune and Autopilot ESP diagnostics, DSRegCmd analysis, and real-time log tailing.

Screenshots

Log Viewer

Format auto-detection, severity color coding, and one-click Windows error-code lookup.

Intune Diagnostics

A color-coded event timeline for Win32 apps, scripts, and downloads — success and failure at a glance.

ESP Diagnostics

A single-page Autopilot and Device Preparation cockpit with actionable workload, MSIEXEC, coverage, and live-log evidence.

DSRegCmd Troubleshooting

Device join posture, PRT and certificate health, and prioritized issue cards.

Screenshots are generated by npm run screenshots. See [screenshots/README.md](screenshots/README.md).

Editions: Full vs Lite

CMTrace Open ships as two standalone builds from the same source. Both are single-file executables with no installer or dependencies. The download page labels them "full edition" and "lite edition". Choose Full unless you specifically want the smallest possible download - it is the default build and includes everything.

Full edition (default)

The complete tool: the log viewer plus every specialized troubleshooting feature.

Lite edition

The core log viewer only. It keeps everything under Log Viewer below - format auto-detection, real-time tailing, virtual scrolling, find and filter, text highlighting, and the embedded error-code database - plus the Timeline and DNS / DHCP tools. It leaves out the nine specialized features above, which also drops the Windows Event Log and property-list parsers and makes the binary noticeably smaller. Choose Lite if you just want a fast, portable, CMTrace-style log reader with a minimal footprint.

Both editions read the same log formats and share the same viewer, so a log you can open in Full opens identically in Lite.

Features

Log Viewer

• Auto-detection — automatically identifies CCM, CBS, DISM, Panther, simple, and plain text log formats
• Real-time tailing — live file watching with pause/resume
• Virtual scrolling — smooth performance with 100K+ line files