diff --git a/.github/workflows/builds.yml b/.github/workflows/builds.yml
index c784a4810395..c0b987900b5b 100644
--- a/.github/workflows/builds.yml
+++ b/.github/workflows/builds.yml
@@ -1312,7 +1312,8 @@ jobs:
 
   macos-latest:
     name: MacOS Latest
-    runs-on: macos-latest
+    # use 10.15 for now. Build fails on macos-11 (aka macos-latest)
+    runs-on: macos-10.15
     needs: [prepare-deps]
     steps:
       # Cache Rust stuff.