diff --git a/.github/workflows/run_tests.yml b/.github/workflows/run_tests.yml
index e246d6f..848593a 100644
--- a/.github/workflows/run_tests.yml
+++ b/.github/workflows/run_tests.yml
@@ -24,7 +24,7 @@ jobs:
           - { name: linux-python3.12           , requirements: pinned ,  python-ver: "3.12", os: ubuntu-latest }
           - { name: windows-python3.7-minimum  , requirements: minimum,  python-ver: "3.7" , os: windows-latest }
           - { name: windows-python3.12         , requirements: pinned ,  python-ver: "3.12", os: windows-latest }
-          - { name: macos-python3.7-minimum    , requirements: minimum,  python-ver: "3.7" , os: macos-latest }
+          - { name: macos-python3.7-minimum    , requirements: minimum,  python-ver: "3.7" , os: macos-13 }
           - { name: macos-python3.12           , requirements: pinned ,  python-ver: "3.12", os: macos-latest }
     steps:
       - name: Checkout repo