diff --git a/packages/pigeon/example/app/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme b/packages/pigeon/example/app/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
index d795332e1b7b..e6f213fc04a5 100644
--- a/packages/pigeon/example/app/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
+++ b/packages/pigeon/example/app/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
@@ -57,7 +57,7 @@
       <Testables>
          <TestableReference
             skipped = "NO"
-            parallelizable = "YES">
+            parallelizable = "NO">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "331C8080294A63A400263BE5"
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme b/packages/pigeon/platform_tests/alternate_language_test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
index 17337d64b427..5753dbef9f15 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
@@ -58,7 +58,7 @@
       <Testables>
          <TestableReference
             skipped = "NO"
-            parallelizable = "YES">
+            parallelizable = "NO">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "33AA165E291EB8B600ECBEEB"
diff --git a/packages/pigeon/platform_tests/test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme b/packages/pigeon/platform_tests/test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
index c30cba8d26ff..12cf80a4507b 100644
--- a/packages/pigeon/platform_tests/test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
+++ b/packages/pigeon/platform_tests/test_plugin/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
@@ -58,7 +58,7 @@
       <Testables>
          <TestableReference
             skipped = "NO"
-            parallelizable = "YES">
+            parallelizable = "NO">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "33A341B4291ECCA100D34E0F"