diff --git a/src/Umbraco.Core/Models/MemberType.cs b/src/Umbraco.Core/Models/MemberType.cs
index e324b78447..aea28e20c5 100644
--- a/src/Umbraco.Core/Models/MemberType.cs
+++ b/src/Umbraco.Core/Models/MemberType.cs
@@ -44,7 +44,9 @@ namespace Umbraco.Core.Models
 
                 SetPropertyValueAndDetectChanges(o =>
                 {
-                    _alias = value == "_umbracoSystemDefaultProtectType" ? value : value.ToSafeAlias();
+                    _alias = value == "_umbracoSystemDefaultProtectType" 
+                        ? value 
+                        : (value == null ? string.Empty : value.ToSafeAlias() );
                     return _alias;
                 }, _alias, AliasSelector);
             }
diff --git a/src/Umbraco.Core/Persistence/Repositories/MemberTypeRepository.cs b/src/Umbraco.Core/Persistence/Repositories/MemberTypeRepository.cs
index 9875943f33..ea95936d32 100644
--- a/src/Umbraco.Core/Persistence/Repositories/MemberTypeRepository.cs
+++ b/src/Umbraco.Core/Persistence/Repositories/MemberTypeRepository.cs
@@ -166,8 +166,10 @@ namespace Umbraco.Core.Persistence.Repositories
 
         protected override void PersistNewItem(IMemberType entity)
         {
-            ((MemberType)entity).AddingEntity();
+            ValidateAlias(entity);
 
+            ((MemberType)entity).AddingEntity();
+            
             //By Convention we add 9 stnd PropertyTypes to an Umbraco MemberType
             entity.AddPropertyGroup(Constants.Conventions.Member.StandardPropertiesGroupName);
             var standardPropertyTypes = Constants.Conventions.Member.GetStandardPropertyTypeStubs();
diff --git a/src/Umbraco.Tests/Persistence/Repositories/MemberTypeRepositoryTest.cs b/src/Umbraco.Tests/Persistence/Repositories/MemberTypeRepositoryTest.cs
index 5f00e5b4b7..eba4a9cdc1 100644
--- a/src/Umbraco.Tests/Persistence/Repositories/MemberTypeRepositoryTest.cs
+++ b/src/Umbraco.Tests/Persistence/Repositories/MemberTypeRepositoryTest.cs
@@ -1,4 +1,5 @@
-using System.Linq;
+using System;
+using System.Linq;
 using NUnit.Framework;
 using Umbraco.Core;
 using Umbraco.Core.Models;
@@ -70,6 +71,21 @@ namespace Umbraco.Tests.Persistence.Repositories
             }
         }
 
+        [Test]
+        public void Cannot_Persist_Member_Type_Without_Alias()
+        {
+            var provider = new PetaPocoUnitOfWorkProvider();
+            var unitOfWork = provider.GetUnitOfWork();
+            using (var repository = CreateRepository(unitOfWork))
+            {
+                var memberType = MockedContentTypes.CreateSimpleMemberType();
+                memberType.Alias = null;
+                repository.AddOrUpdate(memberType);
+
+                Assert.Throws<InvalidOperationException>(unitOfWork.Commit);
+            }
+        }
+
         [Test]
         public void Can_Get_All_Member_Types()
         {