Error adding users to Microsoft Dynamics CRM 4.0.

Today I came across an issue with CRM 4.0 where one of our dedicated installations with its own Active Directory could not add users into CRM.Naturally, the error displayed inside CRM was a generic error message with no specific information of any helpful nature. 

The error from the Trace Logs was as follows :  

[2009-01-15 11:37:47.8] Process: w3wp |Organization:373c636e-eaf2-404d-bf10-979cb92e39d3 |Thread:    8 |Category: Platform |User: 2d9d9775-7b3b-4a62-bde2-aaee539c8aa5 |Level: Error | MessageProcessor.Execute
>MessageProcessor fail to process message 'Create' for 'systemuser'.
[2009-01-15 11:37:47.8] Process: w3wp |Organization:373c636e-eaf2-404d-bf10-979cb92e39d3 |Thread:    8 |Category: Exception |User: 2d9d9775-7b3b-4a62-bde2-aaee539c8aa5 |Level: Error | CrmException..ctor
 at CrmException..ctor(String message, Exception innerException, Int32 errorCode)
 at SoapExtensionExceptionHandlerBase.GetCrmException(Exception exception)
 at InProcessCrmService.Execute(Object request)
 at PlatformCommand.ExecuteInternal()
 at CreateCommand.Execute()
 at SystemUser.Create(Boolean performDuplicateCheck)
 at EntityProxy.CreateAndRetrieve(String columnSet, Boolean performDuplicateCheck)
 at AppForm.RaiseDataEvent(FormEventId eventId)
 at EndUserForm.Initialize(Entity entity)
 at CustomizableForm.Execute(Entity entity, String formType)
 at SystemUserDetailPage.ConfigureForm()
 at AppUIPage.OnPreRender(EventArgs e)
 at Control.PreRenderRecursiveInternal()
 at Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 at Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 at Page.ProcessRequest()
 at Page.ProcessRequest(HttpContext context)
 at biz_users_edit_aspx.ProcessRequest(HttpContext context)
 at CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
 at HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
 at ApplicationStepManager.ResumeSteps(Exception error)
 at HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
 at HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr)
 at HttpRuntime.ProcessRequestNoDemand(HttpWorkerRequest wr)
 at ISAPIRuntime.ProcessRequest(IntPtr ecb, Int32 iWRType)

And

>MSCRM Error Report:
——————————————————————————————————–
Error: Exception has been thrown by the target of an invocation.
Error Message: Exception has been thrown by the target of an invocation.
Source File: Not available
Line Number: Not available
Request URL: http://www.crminstallation.com/biz/users/edit.aspx?_CreateFromType=10&_CreateFromId={9CEDFF4E-82CA-DD11-82C1-00215E3F818C}
Stack Trace Info: [UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))]
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   at System.DirectoryServices.DirectoryEntry.Invoke(String methodName, Object[] args)
   at Microsoft.Crm.BusinessEntities.SecurityUtils.AddPrincipalToGroup(Guid principalId, Guid groupId)
   at Microsoft.Crm.BusinessEntities.SecurityLibrary.AddPrincipalToGroup(Guid principalId, Guid groupId)
   at Microsoft.Crm.ObjectModel.SystemUserServiceInternal`1.ManageGroupsHelper(Guid activeDirectoryGuid, Boolean remove, ExecutionContext context)
   at Microsoft.Crm.ObjectModel.SystemUserServiceInternal`1.AddPrincipalToGroups(Guid activeDirectoryGuid, ExecutionContext context)
   at Microsoft.Crm.ObjectModel.SystemUserServiceInternal`1.CreateInternal(Guid organizationId, IBusinessEntity systemuser, ExecutionContext context)
   at Microsoft.Crm.ObjectModel.SystemUserServiceInternal`1.Create(IBusinessEntity systemuser, ExecutionContext context)

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Web.Services.Protocols.LogicalMethodInfo.Invoke(Object target, Object[] values)
   at Microsoft.Crm.Extensibility.InternalOperationPlugin.Execute(IPluginExecutionContext context)
   at Microsoft.Crm.Extensibility.PluginStep.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.Pipeline.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.MessageProcessor.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.InternalMessageDispatcher.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.ExternalMessageDispatcher.Execute(String messageName, Int32 primaryObjectTypeCode, Int32 secondaryObjectTypeCode, PropertyBag fields, CorrelationToken correlationToken, CallerOriginToken originToken, UserAuth userAuth, Guid callerId)
   at Microsoft.Crm.Sdk.RequestBase.Process(Int32 primaryObjectTypeCode, Int32 secondaryObjectTypeCode, CorrelationToken correlationToken, CallerOriginToken originToken, UserAuth userAuth, Guid callerId)
   at Microsoft.Crm.Sdk.RequestBase.Process(CorrelationToken correlationToken, CallerOriginToken originToken, UserAuth userAuth, Guid callerId)
   at Microsoft.Crm.Sdk.CrmServiceInternal.Execute(RequestBase request, CorrelationToken correlationToken, CallerOriginToken originToken, UserAuth userAuth, Guid callerId)
   at Microsoft.Crm.Sdk.InProcessCrmService.Execute(Object request)
   at Microsoft.Crm.Application.Platform.ServiceCommands.PlatformCommand.ExecuteInternal()
   at Microsoft.Crm.Application.Platform.ServiceCommands.CreateCommand.Execute()
   at Microsoft.Crm.Application.Platform.SystemUser.Create(Boolean performDuplicateCheck)
   at Microsoft.Crm.Application.Platform.EntityProxy.CreateAndRetrieve(String columnSet, Boolean performDuplicateCheck)
   at Microsoft.Crm.Application.Forms.AppForm.RaiseDataEvent(FormEventId eventId)

Fortunately I had seen this one before, and fixing it is pretty easy.  Just switch the registry entry HKLMMicrosoftMSCRMAutoGroupManagement from 0 to 1.