[Flaky Test] Microsoft.Build.Engine.UnitTests.MSBuildServer_Tests.CanShutdownServerProcess

**Flaky-test key** (automated de-duplication — do not edit):
```text
flaky-test-id: Microsoft.Build.Engine.UnitTests.MSBuildServer_Tests.CanShutdownServerProcess
```

## Evidence

This test has been flagged as flaky by the automated flaky-test detector.

- **Distinct sources:** 3 (rolling `main` builds only)
- **Rolling build IDs:** [1464065](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1464065), [1475010](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1475010), [1481906](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1481906)
- **Total failures:** 8
- **Distinct error signatures:** 4 (indicating non-deterministic failure modes)
- **Legs:** FullOnWindows, FullOnWindows Release
- **TFMs:** net472
- **Assembly:** `Microsoft.Build.CommandLine.UnitTests`
- **First seen:** 2026-06-15
- **Last seen:** 2026-06-25
- **Sample build:** [1464065](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1464065)

### Representative error

```
System.InvalidOperationException : Couldn't get process information from performance counter.
---- System.ComponentModel.Win32Exception : Unknown error (0xc0000017)
```

## Location

- **Fully-qualified name:** `Microsoft.Build.Engine.UnitTests.MSBuildServer_Tests.CanShutdownServerProcess`
- **Assembly:** `Microsoft.Build.CommandLine.UnitTests`
- **Source:** `src/MSBuild.UnitTests/MSBuildServer_Tests.cs` (line ~278)
- **Project:** `src/MSBuild.UnitTests/Microsoft.Build.CommandLine.UnitTests.csproj`

## Next steps

This test will be quarantined via `[ActiveIssue("https://github.com/dotnet/msbuild/issues/")]` (from `Microsoft.DotNet.XUnitV3Extensions`, namespace `Xunit`) — not `[Fact(Skip=...)]` — until the underlying nondeterminism is fixed. The quarantine pipeline (definition 344, `azure-pipelines/quarantine.yml`) will continue running this test on Windows/Linux/macOS across main's rolling builds to gather failure signal over time.

> Generated by [Flaky Test Triage](https://github.com/dotnet/msbuild/actions/runs/28288806840) · 405.3 AIC · ⊞ 34.9K · [◷](https://github.com/search?q=repo%3Adotnet%2Fmsbuild+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Fmsbuild%2Fflaky-test-detector.agent%22&type=issues)

Start with Microsoft.Build.Engine.UnitTests.MSBuildServer_Tests.CanShutdownServerProcess in src/MSBuild.UnitTests/MSBuildServer_Tests.cs around line 278, and run the Microsoft.Build.CommandLine.UnitTests project on the affected Windows net472 configuration. Review the performance-counter failure and the quarantined test runs in the listed rolling builds. Done means the test no longer exhibits nondeterministic failures and can leave quarantine.

Written by the indexing model from the issue text.