diff --git a/.github/workflows/pnl-ci.yml b/.github/workflows/pnl-ci.yml
index c9e7940e4cb..797234f1580 100644
--- a/.github/workflows/pnl-ci.yml
+++ b/.github/workflows/pnl-ci.yml
@@ -22,7 +22,7 @@ jobs:
       matrix:
         python-version: [3.7, 3.8, 3.9]
         python-architecture: ['x64']
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest, macos-10.15, windows-latest]
         include:
           # add 32-bit build on windows
           - python-version: 3.8