diff --git a/Pilz/Runtime/OSType.vb b/Pilz/Runtime/OSType.vb
index caf344b..477cc87 100644
--- a/Pilz/Runtime/OSType.vb
+++ b/Pilz/Runtime/OSType.vb
@@ -1,6 +1,7 @@
 Namespace Runtime
 
     Public Enum OSType
+        Unknown
         Windows
         Linux
         OSX