What does HRESULT 0x87C51010 (UTC_E_PERFTRACK_ALREADY_TRACING) mean?

UTC_E_PERFTRACK_ALREADY_TRACING

Interpret the result in context: PerfTrack trace ownership

UTC_E_PERFTRACK_ALREADY_TRACING has the unsigned value 0x87C51010. In UTC it comes from ETW trace-session control, where PerfTrack trace ownership owns the decision. Start by locating the exact scenario-engine boundary that emitted this value. The immediate contract failed because the PerfTrack component already controls a tracing session and rejected another start, so diagnosis should remain at that boundary until a controlled comparison crosses it.

The Universal Telemetry Client controls ETW sessions on behalf of diagnostic scenarios. ETW sessions have controller-owned names, in-memory buffers, providers, logging modes and lifetimes; a status at this layer should be correlated with the actual session list rather than inferred from the presence of an ETL file.

Build a minimal evidence set

Run an A/B check

1. Export the relevant Microsoft-Windows-UniversalTelemetryClient/Operational events and preserve their ActivityId or request correlation alongside this result.
2. Capture PerfTrack session name, controller PID, active profiles, start time, stackwalk/provider settings and caller. Do this before restarting the service or deleting any working directory.
3. Perform this one-variable comparison: stop the existing PerfTrack capture normally and start the requested profile once.
4. After the comparison, record the next HRESULT and whether the requested session, action, trigger or output object was actually created.

Nearby result: UTC_E_ALTERNATIVE_TRACE_CANNOT_PREEMPT — is based on priority arbitration, not specifically PerfTrack ownership.

Trace-session note

Use an ETW controller view to list session name, GUID, mode, buffers and enabled providers while this result is active. The presence of an ETL file from an earlier run is not proof that the required in-memory session currently exists or is owned by UTC.

Safe remediation

Coordinate with the existing controller rather than forcibly stopping all ETW sessions.

Technical references

• Microsoft Open Specifications: Windows error-code registry — reference for ETW trace-session control while interpreting this result.
• Microsoft: Universal Telemetry Client configuration diagnosis — reference for ETW trace-session control while interpreting it.
• Microsoft: Event Tracing for Windows
• Microsoft: WPR and ETW sessions