diff --git a/Services/SclSafeTrialRunner.cs b/Services/SclSafeTrialRunner.cs
index 4b8490600..686e811c8 100644
--- a/Services/SclSafeTrialRunner.cs
+++ b/Services/SclSafeTrialRunner.cs
@@ -127,7 +127,8 @@ public static async Task<SclSafeTrialRunResult> RunAsync(
             var document = XDocument.Load(command.SclPath, LoadOptions.PreserveWhitespace | LoadOptions.SetLineInfo);
             var sclXml = document.ToString(SaveOptions.DisableFormatting);
 
-            var client = new NativeIec61850Client();
+            // Own the entire read-only trial association, including failure and cancellation.
+            await using var client = new NativeIec61850Client();
             result = await client.ConnectUsingSclAsync(
                 sclXml,
                 command.IedName,
diff --git a/tests/ARSAS.Tests/SclSafeTrialRunnerTests.cs b/tests/ARSAS.Tests/SclSafeTrialRunnerTests.cs
index 5e23a1e9a..f53a6afa5 100644
--- a/tests/ARSAS.Tests/SclSafeTrialRunnerTests.cs
+++ b/tests/ARSAS.Tests/SclSafeTrialRunnerTests.cs
@@ -67,6 +67,19 @@ public void CommandParser_RejectsInvalidMmsPort(string port)
         Assert.Contains("port", error, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public void TrialRunner_SourceContract_DisposesTrialClientOnEveryExit()
+    {
+        var source = File.ReadAllText(FindRepoFile("Services/SclSafeTrialRunner.cs"));
+
+        // An awaited using declaration includes normal return, cancellation and
+        // exception paths, and keeps the association alive for snapshot capture.
+        Assert.Contains(
+            "await using var client = new NativeIec61850Client();",
+            source,
+            StringComparison.Ordinal);
+    }
+
     [Fact]
     public void TrialRunner_SourceContract_HasNoDiscoveryWriteControlOrReportingEntryPoint()
     {