@@ -137,6 +137,7 @@ jobs:
         shell: powershell
         run: |
           $ErrorActionPreference = "Stop"
+          $ProgressPreference = "SilentlyContinue"
           $version = "7.4.20"
           $archive = Join-Path $env:RUNNER_TEMP "PowerShell-$version-win-arm64.zip"
           $installDir = Join-Path $env:RUNNER_TEMP "powershell-$version-arm64"
@@ -148,10 +149,19 @@ jobs:
             throw "PowerShell archive checksum mismatch"
           }
           Expand-Archive -Path $archive -DestinationPath $installDir
-          $installDir >> $env:GITHUB_PATH
+          $installDir | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
           & "$installDir\pwsh.exe" -NoProfile -NonInteractive -Command '$PSVersionTable; [System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture'
           if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
 
+      - name: Verify Windows ARM PowerShell selection
+        if: inputs.platform == 'win' && inputs.arch == 'arm64'
+        shell: pwsh
+        run: |
+          $expectedPath = Join-Path $env:RUNNER_TEMP "powershell-7.4.20-arm64\pwsh.exe"
+          if ((Get-Command pwsh.exe).Source -ne $expectedPath -or $PSVersionTable.PSVersion -ne [version]"7.4.20") {
+            throw "Windows ARM builds must use the pinned PowerShell runtime"
+          }
+
       # Windows installs straight from the registry. There, linking the packages
       # takes the time, not downloading them, so a ~700 MB package cache did not
       # pay for its own restore. Across recent nightlies, restore plus install