diff --git a/src/Umbraco.Core/Persistence/Factories/UserGroupFactory.cs b/src/Umbraco.Core/Persistence/Factories/UserGroupFactory.cs
index 20057db20f..f4ecffca54 100644
--- a/src/Umbraco.Core/Persistence/Factories/UserGroupFactory.cs
+++ b/src/Umbraco.Core/Persistence/Factories/UserGroupFactory.cs
@@ -13,7 +13,7 @@ namespace Umbraco.Core.Persistence.Factories
             var userGroup = new UserGroup(dto.UserCount, dto.Alias, dto.Name,
                 dto.DefaultPermissions.IsNullOrWhiteSpace()
                     ? Enumerable.Empty<string>()
-                    : dto.DefaultPermissions.ToCharArray().Select(x => x.ToString(CultureInfo.InvariantCulture)),
+                    : dto.DefaultPermissions.ToCharArray().Select(x => x.ToString(CultureInfo.InvariantCulture)).ToList(),
                 dto.Icon);
 
             try
diff --git a/src/Umbraco.Tests/Models/Mapping/UserModelMapperTests.cs b/src/Umbraco.Tests/Models/Mapping/UserModelMapperTests.cs
new file mode 100644
index 0000000000..7f5e975cfc
--- /dev/null
+++ b/src/Umbraco.Tests/Models/Mapping/UserModelMapperTests.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutoMapper;
+using Moq;
+using Newtonsoft.Json;
+using NUnit.Framework;
+using Umbraco.Core;
+using Umbraco.Core.Models.Membership;
+using Umbraco.Tests.TestHelpers;
+using Umbraco.Web.Models.ContentEditing;
+using Umbraco.Web.Models.Mapping;
+
+namespace Umbraco.Tests.Models.Mapping
+{
+    [TestFixture]
+    [DatabaseTestBehavior(DatabaseBehavior.NewDbFileAndSchemaPerTest)]
+    public class UserModelMapperTests : BaseDatabaseFactoryTest
+    {
+        [Test]
+        public void Map_UserGroupSave_To_IUserGroup()
+        {
+            var userModelMapper = new UserModelMapper();
+            Mapper.Initialize(configuration => userModelMapper.ConfigureMappings(configuration, ApplicationContext.Current));
+
+            var userService = ApplicationContext.Services.UserService;
+            IUserGroup userGroup = new UserGroup(0, "alias", "name", new List<string> { "c" }, "icon");
+            userService.Save(userGroup);
+
+            // userGroup.permissions is System.Collections.Generic.List`1[System.String]
+
+            userGroup = userService.GetUserGroupById(userGroup.Id);
+
+            // userGroup.permissions is System.Linq.Enumerable+WhereSelectArrayIterator`2[System.Char, System.String]
+            // fixed: now System.Collections.Generic.List`1[System.String]
+
+            const string json = "{\"id\":@@@ID@@@,\"alias\":\"perm1\",\"name\":\"Perm1\",\"icon\":\"icon-users\",\"sections\":[\"content\"],\"users\":[],\"defaultPermissions\":[\"F\",\"C\",\"A\"],\"assignedPermissions\":{},\"startContentId\":-1,\"startMediaId\":-1,\"action\":\"save\",\"parentId\":-1}";
+            var userGroupSave = JsonConvert.DeserializeObject<UserGroupSave>(json.Replace("@@@ID@@@", userGroup.Id.ToString()));
+
+            // failed, AutoMapper complained, "Unable to cast object of type 'WhereSelectArrayIterator`2[System.Char,System.String]' to type 'System.Collections.IList'".
+            // fixmed: added ToList() in UserGroupFactory
+            Mapper.Map(userGroupSave, userGroup);
+        }
+    }
+}
diff --git a/src/Umbraco.Tests/Umbraco.Tests.csproj b/src/Umbraco.Tests/Umbraco.Tests.csproj
index 5a9a79db47..3d4a8d7320 100644
--- a/src/Umbraco.Tests/Umbraco.Tests.csproj
+++ b/src/Umbraco.Tests/Umbraco.Tests.csproj
@@ -186,6 +186,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Cache\CacheRefresherEventHandlerTests.cs" />
+    <Compile Include="Models\Mapping\UserModelMapperTests.cs" />
     <Compile Include="TestHelpers\ControllerTesting\AuthenticateEverythingExtensions.cs" />
     <Compile Include="TestHelpers\ControllerTesting\AuthenticateEverythingMiddleware.cs" />
     <Compile Include="TestHelpers\ControllerTesting\SpecificAssemblyResolver.cs" />