Test failure: async.WorkItemExecution failed with System.PlatformNotSupportedException
Author: VincentBuCreated Sep 16, 2026Updated Sep 18, 2026
Labelsuntriagedarea-VM-threading-monoblocking-outerloopKnown Build Error
Build Information
Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1597898 Build error leg or test failing: async.WorkItemExecution
Error Details
System.PlatformNotSupportedException: Operation is not supported on this platform.
at System.Runtime.CompilerServices.RuntimeFeature.ThrowIfMultithreadingIsNotSupported()
at System.Threading.Tasks.Task.InternalWaitCore(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at System.Threading.Tasks.Task.InternalWait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at Runtime_125615.TestEntryPoint()
at Program.<<Main>$>g__TestExecutor2|0_3(StreamWriter tempLogSw, StreamWriter statsCsvSw, StreamWriter outOfProcessPlanWriter, <>c__DisplayClass0_0&)Error Message
Fill the error message using step by step known issues guidance.
{
"ErrorMessage": "Failed test: async.WorkItemExecution",
"BuildRetry": false,
"ExcludeConsoleLog": false
}Known issue validation
Build: :mag_right: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1597898
Error message validated: [Failed test: async.WorkItemExecution]
Result validation: :x: Known issue did not match with the provided build.
Validation performed at: 9/16/2026 1:32:37 AM UTC
Report
Summary
| 24-Hour Hit Count | 7-Day Hit Count | 1-Month Count |
|---|---|---|
| 0 | 0 | 0 |
Source: dotnet/runtime