diff --git a/src/Microsoft.AspNet.Diagnostics/project.json b/src/Microsoft.AspNet.Diagnostics/project.json
index 7a8865035e..2978023dc5 100644
--- a/src/Microsoft.AspNet.Diagnostics/project.json
+++ b/src/Microsoft.AspNet.Diagnostics/project.json
@@ -15,7 +15,7 @@
         "System.Diagnostics.Tools": "4.0.0.0",
         "System.Globalization": "4.0.10.0",
         "System.IO": "4.0.0.0",
-        "System.IO.FileSystem": "4.0.10.0",
+        "System.IO.FileSystem": "4.0.0.0",
         "System.Linq": "4.0.0.0",
         "System.Reflection": "4.0.10.0",
         "System.Resources.ResourceManager": "4.0.0.0",