Windows Event ID Lookup
Free searchable Windows Event ID reference. Look up common Security, System, Application, and Task Scheduler event IDs and what they mean.
Why this is a curated list, not the full catalog
The full Windows Event ID space runs into the thousands once every provider, feature, and application is counted — most of which nobody ever looks up because they never come up in day-to-day troubleshooting. This tool sticks to a curated shortlist of the IDs that actually show up repeatedly during real incident response and auditing work — failed logons, service failures, scheduled task issues, Group Policy processing errors — on the theory that a fast, memorable reference for the common 5% beats an exhaustive but unwieldy list of everything. For anything not covered here, Microsoft's own event ID documentation and the specific provider's log source are the authoritative next step.