diff --git a/src/csharp/Grpc.Tools.Tests/Grpc.Tools.Tests.csproj b/src/csharp/Grpc.Tools.Tests/Grpc.Tools.Tests.csproj
index 661d97d81bc..7c1a6afe343 100644
--- a/src/csharp/Grpc.Tools.Tests/Grpc.Tools.Tests.csproj
+++ b/src/csharp/Grpc.Tools.Tests/Grpc.Tools.Tests.csproj
@@ -9,6 +9,18 @@
+
+
+
+ /usr/lib/mono/4.5-api
+ /usr/local/lib/mono/4.5-api
+ /Library/Frameworks/Mono.framework/Versions/Current/lib/mono/4.5-api
+
+