diff --git a/tools/internal_ci/windows/grpc_run_tests_matrix.bat b/tools/internal_ci/windows/grpc_run_tests_matrix.bat
index d63b9133a1c..ecb2fa76592 100644
--- a/tools/internal_ci/windows/grpc_run_tests_matrix.bat
+++ b/tools/internal_ci/windows/grpc_run_tests_matrix.bat
@@ -22,6 +22,9 @@ IF "%cd%"=="T:\src" (
 )
 endlocal
 
+@rem Info on disk usage
+dir t:\
+
 @rem enter repo root
 cd /d %~dp0\..\..\..
 
@@ -48,4 +51,7 @@ set RUNTESTS_EXITCODE=%errorlevel%
 @rem show ccache stats
 ccache --show-stats
 
+@rem Info on disk usage after test
+dir t:\
+
 exit /b %RUNTESTS_EXITCODE%
diff --git a/tools/run_tests/run_tests_matrix.py b/tools/run_tests/run_tests_matrix.py
index 90eb52b8032..518c54762cf 100755
--- a/tools/run_tests/run_tests_matrix.py
+++ b/tools/run_tests/run_tests_matrix.py
@@ -416,17 +416,18 @@ def _create_portability_test_jobs(
     # TODO(jtattermusch): The C tests with exactly the same config are already running as part of the
     # basictests_c suite (so we force --build_only to avoid running them twice).
     # The C++ tests aren't all passing, so also force --build_only.
-    test_jobs += _generate_jobs(
-        languages=["c", "c++"],
-        configs=["dbg"],
-        platforms=["windows"],
-        arch="x64",
-        compiler="cmake_ninja_vs2019",
-        labels=["portability", "corelang"],
-        extra_args=extra_args + ["--build_only"],
-        inner_jobs=inner_jobs,
-        timeout_seconds=_CPP_RUNTESTS_TIMEOUT,
-    )
+    # NOTE(veblush): This is not neded as default=cmake_ninja_vs2019
+    # test_jobs += _generate_jobs(
+    #     languages=["c", "c++"],
+    #     configs=["dbg"],
+    #     platforms=["windows"],
+    #     arch="x64",
+    #     compiler="cmake_ninja_vs2019",
+    #     labels=["portability", "corelang"],
+    #     extra_args=extra_args + ["--build_only"],
+    #     inner_jobs=inner_jobs,
+    #     timeout_seconds=_CPP_RUNTESTS_TIMEOUT,
+    # )
 
     # C and C++ with no-exceptions on Linux
     test_jobs += _generate_jobs(