diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index edaa6555b..00a500974 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -165,7 +165,7 @@ jobs:
       matrix:
         os:
           - ubuntu-22.04
-          - macos-13
+          - macos-12
         python-version:
           - "3.9"
           - "3.10"
@@ -186,9 +186,17 @@ jobs:
       - name: Setup Docker (missing on MacOS)
         if: runner.os == 'macOS'
         run: ./hack/install-docker-macos.sh
-      - name: Install OpenMP (in MacOS)
-        if: runner.os == 'macOS'
-        run: brew install libomp
+      - name: Downgrade OpenMP (in MacOS)
+        if: runner.os == 'macos'
+        run: |
+          # Recent versions of OpenMP cause segfaults in MacOS when training
+          # LightGBM / XGBoost models (but only when Torch is present)
+          # https://github.com/microsoft/LightGBM/issues/4229
+          # https://github.com/autogluon/autogluon/issues/1442
+          wget https://raw.githubusercontent.com/chenrui333/homebrew-core/0094d1513ce9e2e85e07443b8b5930ad298aad91/Formula/libomp.rb
+          brew unlink libomp
+          brew install --build-from-source ./libomp.rb
+          brew list --version libomp
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
         with:
diff --git a/tox.ini b/tox.ini
index 56905ebaa..e4a6e37be 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,11 +20,14 @@ commands_pre =
     poetry install --sync --no-root
 commands =
     python -m pytest {posargs} -n auto \
-        {toxinidir}/tests --ignore={toxinidir}/tests/kafka
-    # kafka tests are failinig for macos when running in parallel
+        {toxinidir}/tests \
+        --ignore={toxinidir}/tests/kafka \
+        --ignore={toxinidir}/tests/parallel
+    # kafka and parallel tests are failing for macos when running in parallel
     # with the entire test suite. So, we run them separately.
-    python -m pytest {posargs} -n auto \
-        {toxinidir}/tests/kafka
+    python -m pytest {posargs} \
+        {toxinidir}/tests/kafka \
+        {toxinidir}/tests/parallel
 set_env =
     GITHUB_SERVER_URL = {env:GITHUB_SERVER_URL:https\://github.com}
     GITHUB_REPOSITORY = {env:GITHUB_REPOSITORY:SeldonIO/MLServer}
@@ -46,11 +49,13 @@ commands =
         {toxinidir}/runtimes/lightgbm \
         {toxinidir}/runtimes/mlflow \
         {toxinidir}/runtimes/huggingface \
-        --ignore={toxinidir}/tests/kafka
-    # kafka tests are failinig for macos when running in parallel
+        --ignore={toxinidir}/tests/kafka \
+        --ignore={toxinidir}/tests/parallel
+    # kafka and parallel tests are failinig for macos when running in parallel
     # with the entire test suite. So, we run them separately.
-    python -m pytest {posargs} -n auto \
-        {toxinidir}/tests/kafka
+    python -m pytest {posargs} \
+        {toxinidir}/tests/kafka \
+        {toxinidir}/tests/parallel
 set_env =
     GITHUB_SERVER_URL = {env:GITHUB_SERVER_URL:https\://github.com}
     GITHUB_REPOSITORY = {env:GITHUB_REPOSITORY:SeldonIO/MLServer}