diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0f12f1a..f3c9920 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -21,7 +21,7 @@ jobs:
 
     strategy:
       matrix:
-        os: ['ubuntu-18.04', 'ubuntu-20.04', 'macos-latest', 'macos-11']
+        os: ['ubuntu-18.04', 'ubuntu-20.04', 'macos-10.15', 'macos-11']
         cc: ['gcc', 'clang']
 
     steps: