diff --git a/nanoFramework.CoreLibrary/System/Convert.cs b/nanoFramework.CoreLibrary/System/Convert.cs
index e040ec9..7ce6ca9 100644
--- a/nanoFramework.CoreLibrary/System/Convert.cs
+++ b/nanoFramework.CoreLibrary/System/Convert.cs
@@ -9,7 +9,6 @@ namespace System
     /// Specifies whether relevant Convert.ToBase64CharArray and Convert.ToBase64String methods insert line breaks in their output.
     /// </summary>
     [Flags]
-    [ExcludeType]
     public enum Base64FormattingOptions
     {
         /// <summary>
diff --git a/nanoFramework.CoreLibrary/System/DateTime.cs b/nanoFramework.CoreLibrary/System/DateTime.cs
index ed428be..7f5ce94 100644
--- a/nanoFramework.CoreLibrary/System/DateTime.cs
+++ b/nanoFramework.CoreLibrary/System/DateTime.cs
@@ -17,7 +17,6 @@ namespace System
     /// nanoFramework doesn't support local time, only  UTC, so it's not possible to specify <see cref="Local"/>.
     /// </remarks>
     [Serializable]
-    [ExcludeType]
     public enum DateTimeKind
     {
         /// <summary>
diff --git a/nanoFramework.CoreLibrary/System/DayOfWeek.cs b/nanoFramework.CoreLibrary/System/DayOfWeek.cs
index 9bb828d..dbd4054 100644
--- a/nanoFramework.CoreLibrary/System/DayOfWeek.cs
+++ b/nanoFramework.CoreLibrary/System/DayOfWeek.cs
@@ -9,7 +9,6 @@ namespace System
     /// Specifies the day of the week.
     /// </summary>
     [Serializable]
-    [ExcludeType]
     public enum DayOfWeek
     {
         /// <summary>
diff --git a/nanoFramework.CoreLibrary/System/IO/IOException.cs b/nanoFramework.CoreLibrary/System/IO/IOException.cs
index e62b900..2f7fddc 100644
--- a/nanoFramework.CoreLibrary/System/IO/IOException.cs
+++ b/nanoFramework.CoreLibrary/System/IO/IOException.cs
@@ -14,7 +14,6 @@ public class IOException : SystemException
         /// <summary>
         /// Provides values for error codes.
         /// </summary>
-        [ExcludeType]
         public enum IOExceptionErrorCode
         {
             /// <summary>
diff --git a/nanoFramework.CoreLibrary/System/Reflection/AssemblyNameFlags.cs b/nanoFramework.CoreLibrary/System/Reflection/AssemblyNameFlags.cs
index 6a54ec6..280f822 100644
--- a/nanoFramework.CoreLibrary/System/Reflection/AssemblyNameFlags.cs
+++ b/nanoFramework.CoreLibrary/System/Reflection/AssemblyNameFlags.cs
@@ -13,7 +13,6 @@ namespace System.Reflection
     /// </summary>
     /// <remarks>Available only in mscorlib build with support for System.Reflection.</remarks>
     [Serializable, Flags]
-    [ExcludeType]
     public enum AssemblyNameFlags
     {
         /// <summary>
diff --git a/nanoFramework.CoreLibrary/System/Reflection/MemberTypes.cs b/nanoFramework.CoreLibrary/System/Reflection/MemberTypes.cs
index b629738..e5ed742 100644
--- a/nanoFramework.CoreLibrary/System/Reflection/MemberTypes.cs
+++ b/nanoFramework.CoreLibrary/System/Reflection/MemberTypes.cs
@@ -13,7 +13,6 @@ namespace System.Reflection
     /// </summary>
     /// <remarks>Available only in mscorlib build with support for System.Reflection.</remarks>
     [Serializable]
-    [ExcludeType]
     public enum MemberTypes
     {
         /// <summary>