MS CRM 4.0 You Cannot Update the Owner Field Using Workflow

PROBLEM:
  • You are using Microsoft CRM 4.0 
  • You cannot update the owner field of an entity in MS CRM 4.0 using workflow because when you click the lookup button on the Owner field, CRM displays an error report with " Exception of type 'System.Web.HttpUnhandledException' was thrown" under the Error Details section and the following appears as the first line under the Full Stack section" [FormatException: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).]" 
  • None of the rollups fix the problem 
  • Client is running Windows Vista 
  • Server is running Windows Server 2003 family, including SBS2003. 


SOLUTION THAT WORKED FOR ME:

You cannot update the owner of a record using the Update step within workflow. You have to do this using the an Assign step instead. The owner field really should be greyed out when using the Update step however this appears to be a bug within CRM.
OTHER POSSIBLE SOLUTIONS:
N/A