diff --git a/src/Microsoft.AspNet.DataProtection/project.json b/src/Microsoft.AspNet.DataProtection/project.json
index 525328fdea..60b6bf893d 100644
--- a/src/Microsoft.AspNet.DataProtection/project.json
+++ b/src/Microsoft.AspNet.DataProtection/project.json
@@ -29,6 +29,7 @@
             "dependencies": {
                 "Microsoft.Win32.Registry": "4.0.0-beta-*",
                 "System.IO": "4.0.10-beta-*",
+                "System.IO.FileSystem": "4.0.0-beta-*",
                 "System.Linq": "4.0.0-beta-*",
                 "System.Reflection.Extensions": "4.0.0-beta-*",
                 "System.Reflection.TypeExtensions": "4.0.0-beta-*",