diff --git a/infra/config/generated/cr-buildbucket.cfg b/infra/config/generated/cr-buildbucket.cfg
index c951e77..01ab643 100644
--- a/infra/config/generated/cr-buildbucket.cfg
+++ b/infra/config/generated/cr-buildbucket.cfg
@@ -32,7 +32,7 @@
       name: "mac"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-13"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "gn"
@@ -110,7 +110,7 @@
       name: "mac"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-13"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "gn"
diff --git a/infra/config/generated/project.cfg b/infra/config/generated/project.cfg
index bb145a6..0462da7 100644
--- a/infra/config/generated/project.cfg
+++ b/infra/config/generated/project.cfg
@@ -7,7 +7,7 @@
 name: "gn"
 access: "group:all"
 lucicfg {
-  version: "1.45.6"
+  version: "1.45.3"
   package_dir: ".."
   config_dir: "generated"
   entry_point: "main.star"
diff --git a/infra/config/main.star b/infra/config/main.star
index f435a6b..e988e49 100755
--- a/infra/config/main.star
+++ b/infra/config/main.star
@@ -98,7 +98,7 @@
     )
 
 ci_builder("linux", "Ubuntu-22.04")
-ci_builder("mac", "Mac-13", caches = [swarming.cache("macos_sdk")])
+ci_builder("mac", "Mac-10.15", caches = [swarming.cache("macos_sdk")])
 ci_builder("win", "Windows-10", caches = [swarming.cache("windows_sdk")])
 
 luci.cq(
@@ -153,5 +153,5 @@
     )
 
 try_builder("linux", "Ubuntu-22.04")
-try_builder("mac", "Mac-13", caches = [swarming.cache("macos_sdk")])
+try_builder("mac", "Mac-10.15", caches = [swarming.cache("macos_sdk")])
 try_builder("win", "Windows-10", caches = [swarming.cache("windows_sdk")])