diff --git a/changelog.d/unreleased/2775.fixed.md b/changelog.d/unreleased/2775.fixed.md
new file mode 100644
index 0000000000..b2c7a790b2
--- /dev/null
+++ b/changelog.d/unreleased/2775.fixed.md
@@ -0,0 +1,17 @@
+---
+category: fixed
+issues:
+  - 2775
+affected:
+  - tests/CodeIndex.Tests/TestConsoleLock.cs
+  - tests/CodeIndex.Tests/ConsoleCaptureTests.cs
+  - tests/CodeIndex.Tests/ChangelogToolTests.cs
+---
+
+## English
+
+- **net9 test runs no longer close shared console capture writers (#2775)** - console capture helpers now restore global streams without disposing captured writers, and changelog console tests run in the non-parallel test collection.
+
+## 日本語
+
+- **net9 テスト実行で共有 console capture writer を閉じないようになりました (#2775)** - console capture helper は global stream を復元しても捕捉 writer を dispose せず、changelog の console テストも非並列 test collection で実行します。
diff --git a/tests/CodeIndex.Tests/ChangelogToolTests.cs b/tests/CodeIndex.Tests/ChangelogToolTests.cs
index f889a93fc7..9ed3cffeb4 100644
--- a/tests/CodeIndex.Tests/ChangelogToolTests.cs
+++ b/tests/CodeIndex.Tests/ChangelogToolTests.cs
@@ -2,6 +2,7 @@
 
 namespace CodeIndex.Tests;
 
+[Collection("SQLite pool sensitive")]
 public sealed class ChangelogToolTests
 {
     [Fact]
diff --git a/tests/CodeIndex.Tests/ConsoleCaptureTests.cs b/tests/CodeIndex.Tests/ConsoleCaptureTests.cs
index 9deea525da..3038698b82 100644
--- a/tests/CodeIndex.Tests/ConsoleCaptureTests.cs
+++ b/tests/CodeIndex.Tests/ConsoleCaptureTests.cs
@@ -1,5 +1,6 @@
 namespace CodeIndex.Tests;
 
+[Collection("SQLite pool sensitive")]
 public class ConsoleCaptureTests
 {
     [Fact]
@@ -33,4 +34,23 @@ public void Capture_RestoresConsoleStreams_WhenActionThrows()
             Assert.Same(originalError, Console.Error);
         }
     }
+
+    [Fact]
+    public void Dispose_DoesNotCloseCapturedWriters()
+    {
+        var stdout = new StringWriter();
+        var stderr = new StringWriter();
+
+        using (var capture = ConsoleCapture.Start(stdout, stderr))
+        {
+            Console.Write("out");
+            Console.Error.Write("err");
+        }
+
+        stdout.Write(" after");
+        stderr.Write(" after");
+
+        Assert.Equal("out after", stdout.ToString());
+        Assert.Equal("err after", stderr.ToString());
+    }
 }
diff --git a/tests/CodeIndex.Tests/TestConsoleLock.cs b/tests/CodeIndex.Tests/TestConsoleLock.cs
index 3192ae8f52..ff89304453 100644
--- a/tests/CodeIndex.Tests/TestConsoleLock.cs
+++ b/tests/CodeIndex.Tests/TestConsoleLock.cs
@@ -86,10 +86,6 @@ public void Dispose()
 
         Restore();
         disposed = true;
-        if (Out is not null)
-            Out.Dispose();
-        if (Error is not null)
-            Error.Dispose();
         System.Threading.Monitor.Exit(TestConsoleLock.Gate);
     }