diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index ee935e216..a03e2c994 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -16,7 +16,7 @@ on:
 
 jobs:
   macOS--dotnet6-and-mono:
-    runs-on: macOS-latest
+    runs-on: macOS-12
     steps:
     - uses: actions/checkout@v1
       with:
@@ -49,7 +49,7 @@ jobs:
         find . -type f -name "*.fsx" | xargs -t -I {} dotnet fsxc {}
 
   macOS--mono-only:
-    runs-on: macOS-latest
+    runs-on: macOS-12
     steps:
     - uses: actions/checkout@v1
       with:
@@ -72,7 +72,7 @@ jobs:
       run: make update-servers
 
   macOS--dotnet6-only:
-    runs-on: macOS-latest
+    runs-on: macOS-12
     steps:
     - uses: actions/checkout@v1
       with: