A client of ours recently reported that they could no longer create custom attributes to an entity in Microsoft Dynamics CRM 4.0. They received a generic "An error has occured" error message when the CRM administrator tried to do this.

After some investigation, we disocvered that they had changed the name of their network's local domain to reflect a change in their company's name. Their network folks went through all the proper processes to implement the change in the Active Directory domain name - except when it came to CRM.