1 files changed, 4 insertions, 2 deletions
diff --git a/src/mscorlib/shared/System/TimeoutException.cs b/src/mscorlib/shared/System/TimeoutException.cs
index 32775a1c56..4ba95bc47b 100644
--- a/src/mscorlib/shared/System/TimeoutException.cs
+++ b/src/mscorlib/shared/System/TimeoutException.cs
@@ -15,7 +15,6 @@ using System.Runtime.Serialization;
 
 namespace System
 {
-    [Serializable]
     public class TimeoutException : SystemException
     {
         public TimeoutException()
@@ -36,6 +35,9 @@ namespace System
             HResult = __HResults.COR_E_TIMEOUT;
         }
 
-        protected TimeoutException(SerializationInfo info, StreamingContext context) : base(info, context) { }
+        protected TimeoutException(SerializationInfo info, StreamingContext context) : base(info, context)
+        {
+            throw new PlatformNotSupportedException();
+        }
     }
 }