Currently, if I try to register a new user I get the following error (on screen) "This user already exists".  I've followed the stack and it appears that it is trying to register a Guest.. following it through this is whats happening:

 
Input:

 Here is the trace (it may look like rubbish but check out the bold line):

     Commerce.MVC.Data.DLL!Commerce.MVC.SqlRepository.DB.Users.get() Line 182
     Commerce.MVC.Data.DLL!Commerce.MVC.Data.SqlUserRepository.GetUsers() Line 22
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 32
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103

>   Commerce.MVC.Data.DLL!Commerce.MVC.Data.SqlUserRepository.GetUsers() Line 22 + 0xd bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 32 + 0xc bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>   Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 32 + 0xc bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>    Commerce.MVC.Data.DLL!Commerce.MVC.Data.UserFilters.WithUserName(System.Linq.IQueryable<Commerce.MVC.Data.User> qry = {SELECT [t0].[UserName], [t0].[FirstName], [t0].[LastName], [t0].[Email]
FROM [dbo].[Users] AS [t0]
}, string userName = "TestName") Line 11    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 32 + 0x17 bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>    Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 32 + 0x17 bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>    Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 36    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>    Commerce.MVC.Data.DLL!Commerce.MVC.Data.User.User(string first = "Guest", string last = "", string userName = "TestName", string email = "anon@nothing.com") Line 21    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 38 + 0x26 bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#
 

>    Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 38 + 0x26 bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#

>    Commerce.MVC.Data.DLL!Commerce.MVC.Data.ShoppingCart.ShoppingCart(string userName = "TestName") Line 25    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.GetUser(string userName = "TestName") Line 39 + 0x15 bytes    C#
     Commerce.MVC.Services.DLL!Commerce.MVC.Services.UserService.Register(Commerce.MVC.Data.User newUser = {Commerce.MVC.Data.User}, string password = "Password", string confirmPassword = "Password", string question = "Question", string answer = "Answer") Line 82 + 0x1a bytes    C#
     Commerce.MVC.Web.DLL!Commerce.MVC.Web.Controllers.UserController.Create() Line 103 + 0x28 bytes    C#