Test failure: async.WorkItemExecution failed with System.PlatformNotSupportedException

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
68/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
csharp
Domain
testing-qa

Research direction

Start with the async.WorkItemExecution failure and the linked Build Analysis known-issue guidance. Compare the supplied ErrorMessage with the failed build result and validation output, then update the issue's known-issue JSON so validation matches the reported failure. Confirm the result against build 1597898.

Written by the indexing model from the issue text.

Description

area-VM-threading-mono blocking-outerloop Known Build Error untriaged

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: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1597898
Error message validated: [Failed test: async.WorkItemExecution]
Result validation: ❌ Known issue did not match with the provided build.
Validation performed at: 9/16/2026 1:32:37 AM UTC

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