diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 830ec8e1..4b81d5c1 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -27,7 +27,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, macos-13]
+        os: [ubuntu-20.04, macos-12]
         mlcomp: [mlkit, mlton]
 #        mlcomp: [mlton]
 #        mlcomp: [mlkit]