diff --git a/build_overrides/build.gni b/build_overrides/build.gni
index 669044db81..582b3efca2 100644
--- a/build_overrides/build.gni
+++ b/build_overrides/build.gni
@@ -41,8 +41,12 @@ if (host_os == "mac") {
   _result = exec_script("//build/mac/should_use_hermetic_xcode.py",
                         [ target_os ],
                         "value")
-  assert(_result != 2,
-         "Do not allow building targets with the default " +
-             "hermetic toolchain if the minimum OS version is not met.")
-  use_system_xcode = _result == 0
+
+  # TODO(crbug.com/904400): Re-enable this once the hermetic toolchain runs on
+  # latest macOS release [Mojave].
+  # assert(_result != 2,
+  #        "Do not allow building targets with the default " +
+  #        "hermetic toolchain if the minimum OS version is not met.")
+  # use_system_xcode = _result == 0
+  use_system_xcode = _result != 1  # Remove when crbug.com/904400 is fixed.
 }