diff --git a/indra/newview/viewer_manifest.py b/indra/newview/viewer_manifest.py
index 4660991de66dedea7e41d921cff28d972a681633..1e43485b9c14d5c2054c48e002c0b704df6d3eb5 100755
--- a/indra/newview/viewer_manifest.py
+++ b/indra/newview/viewer_manifest.py
@@ -1329,6 +1329,10 @@ def package_finish(self):
                     self.run_command([self.src_path_of("installers/darwin/apple-notarize.sh"), app_in_dmg])
 
         finally:
+            # Empirically, on GitHub we've hit errors like:
+            # hdiutil: couldn't eject "disk10" - Resource busy
+            # Try waiting a bit to see if that improves reliability.
+            time.sleep(2)
             # Unmount the image even if exceptions from any of the above 
             self.run_command(['hdiutil', 'detach', '-force', devfile])