What causes "Runtime moniker {runtimeMoniker} is not supported" in dotnet/BenchmarkDotNet?

Upgrade BenchmarkDotNet.Diagnostics.dotTrace to a version whose IsSupported switch covers your moniker.

dotnet/BenchmarkDotNet · error · ArgumentOutOfRangeException

Runtime moniker {runtimeMoniker} is not supported

Error message

Runtime moniker {runtimeMoniker} is not supported

What it means

DotTraceDiagnoser.IsSupported is an exhaustive switch over RuntimeMoniker that throws ArgumentOutOfRangeException on the default branch. Reached only for a moniker value this BDN build does not enumerate at all.

Source

Thrown at src/BenchmarkDotNet.Diagnostics.dotTrace/DotTraceDiagnoser.cs:130

            case RuntimeMoniker.MonoAOTLLVMNet90:
            case RuntimeMoniker.MonoAOTLLVMNet10_0:
            case RuntimeMoniker.MonoAOTLLVMNet11_0:
            case RuntimeMoniker.Mono60:
            case RuntimeMoniker.Mono70:
            case RuntimeMoniker.Mono80:
            case RuntimeMoniker.Mono90:
            case RuntimeMoniker.Mono10_0:
            case RuntimeMoniker.Mono11_0:
                return false;
            case RuntimeMoniker.NetCoreApp20:
            case RuntimeMoniker.NetCoreApp21:
            case RuntimeMoniker.NetCoreApp22:
                return OsDetector.IsWindows();
            case RuntimeMoniker.NetCoreApp30:
            case RuntimeMoniker.NetCoreApp31:
                return OsDetector.IsWindows() || OsDetector.IsLinux();
            default:
                throw new ArgumentOutOfRangeException(nameof(runtimeMoniker), runtimeMoniker, $"Runtime moniker {runtimeMoniker} is not supported");
        }
    }
}

View on GitHub (pinned to b515068b61)

Solutions

Upgrade BenchmarkDotNet.Diagnostics.dotTrace to a version whose IsSupported switch covers your moniker.
If patching, add the missing case returning the desired bool.
Switch the Job to a supported runtime moniker.

Defensive patterns

Strategy: validation

Validate before calling

static readonly HashSet<RuntimeMoniker> DotTraceSupported = new()
{ RuntimeMoniker.Net80, RuntimeMoniker.Net90, RuntimeMoniker.Net60 /* ...per IsSupported */ };
if (!DotTraceSupported.Contains(job.Runtime.Moniker))
    throw new NotSupportedException($"dotTrace diagnoser does not support {job.Runtime.Moniker}; upgrade BDN.");

Prevention

Use a BenchmarkDotNet.Diagnostics.dotTrace build whose IsSupported covers your moniker.
Avoid preview SDKs mapping to monikers not yet enumerated.
Add the missing case in IsSupported when patching BDN.

When it happens

Trigger: A new .NET release introduces a RuntimeMoniker not yet covered by this DotTraceDiagnoser build, or a custom/derived moniker is supplied. Every currently-known moniker returns an explicit true/false.

Common situations: Running on a preview/newer SDK whose moniker postdates this diagnoser build; mismatched BDN engine + diagnoser versions where the engine knows a newer moniker.

Related errors

AI-assisted analysis of dotnet/BenchmarkDotNet@b515068b61 (2026-08-13). Data as JSON: /api/errors/171ce5d63c5606f6. Report an issue: GitHub.