Delete temporary diagnostic files: %TEMP%\Microsoft Diagnostics Hub\ %LOCALAPPDATA%\Microsoft\VisualStudio\<version>\DiagnosticsHub\

If the target process requires elevation, launch Visual Studio with admin rights ( Right-click → Run as administrator ).

Common failure scenarios include:

From the Visual Studio Installer → select More → Repair . This restores missing or corrupted Diagnostic Hub components.

catch (DiagnosticsCollectionStartFailedHubException ex)

Console.WriteLine($"Diagnostic collection failed: ex.Message"); if (ex.InnerException is UnauthorizedAccessException) Console.WriteLine("Try running Visual Studio as Administrator."); // Log to telemetry or retry with fallback configuration

In Visual Studio: Debug → Options → Enable Diagnostic Tools while debugging (uncheck). If the problem disappears, a specific tool (e.g., CPU Usage) is misconfigured. 7. Code Example (Illustrative) You would not typically catch this exception in production code. However, a diagnostic extension or custom profiler host might handle it like this:

| Aspect | Detail | |--------|--------| | Type | Developer-environment exception, not production code | | Primary source | Visual Studio Diagnostic Tools | | Meaning | Failed to begin collecting performance/debug data from a target process | | Most common fix | Run VS as admin, close other profilers, repair VS | | Inner exception significance | High – reveals actual system-level failure | This exception is a diagnostic failure of a diagnostic tool—an ironic but informative error that typically points to environment or permission issues rather than a bug in your application code.

await diagnosticHubSession.StartCollectionAsync(targetProcessId);

Shut down other profilers, performance monitors, or secondary Visual Studio instances debugging the same process.

1. Overview & Context The exception microsoft.diagnosticshub.diagnostics.collectionstartfailedhubexception is a specific, platform-level error originating from Microsoft’s Diagnostic Hub —a component primarily used within Visual Studio and other Microsoft developer tools (like Performance Profiler, CPU Usage tool, Memory Usage tool, and IntelliTrace).