In a Microsoft Exchange Server 2007 environment, a user sends an email message that contains a recipient that uses a custom (non-SMTP) address type. This address only contains spaces. In this situation, the EdgeTransport.exe process crashes and then restarts. Additionally, you find the following events in the Application log:
This issue occurs because an exception is generated by the Exchange Server 2007 server when the custom address only contains spaces.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.