diff --git a/.github/workflows/gh_actions.yml b/.github/workflows/gh_actions.yml
index 7501c21..055bfb6 100644
--- a/.github/workflows/gh_actions.yml
+++ b/.github/workflows/gh_actions.yml
@@ -158,7 +158,7 @@ jobs:
       runs-on: ${{ matrix.os }}
       strategy:
         matrix:
-          os: [ubuntu-latest, windows-latest, macos-latest]
+          os: [ubuntu-latest, windows-latest, macos-10.15]
           python-version: ['3.9']
       steps:
         - uses: actions/checkout@v4