CI: Hosting-1 Windows flaky - DCP fails with 'The directory name is invalid' for dotnet.exe

[davidfowl]

Description

StartAsync_DashboardUrls_DisplayPropertiesSet fails intermittently on Hosting-1 (windows-latest) because DCP cannot launch the local .NET SDK executable.

DCP Error (from run-controllers log)

[2026-03-28T17:08:44.990Z] [error] Failed to start a process fork/exec D:\a\aspire\aspire\.dotnet\dotnet.exe: The directory name is invalid.
[2026-03-28T17:08:44.996Z] [error] An attempt to start the Executable failed fork/exec D:\a\aspire\aspire\.dotnet\dotnet.exe: The directory name is invalid.
[2026-03-28T17:08:44.998Z] [error] The Executable failed to start all available Executable runners have been tried and failed
[2026-03-28T17:08:45.353Z] [error] Could not persist Endpoint object ... Forbidden: new resources cannot be created because the API server is shutting down

This cascades into the API server shutting down and all DCP watches failing with connection refused errors.

Environment

• Runner: windows-latest
• Job: Tests / Hosting-1 / Hosting-1 (windows-latest)
• DCP version: 0.22.9
• .NET SDK path: D:\a\aspire\aspire\.dotnet\dotnet.exe

Example CI run

• Run: https://github.com/microsoft/aspire/actions/runs/23689680435
• Job: https://github.com/microsoft/aspire/actions/runs/23689680435/job/69015576471

Analysis

The local SDK at .dotnet\dotnet.exe exists (the build succeeded) but DCP gets "The directory name is invalid" when trying to exec it. CPU was pegged at 100% per heartbeat logs. This may be a transient Windows runner issue where the working directory or path becomes invalid under high load.