We have a User that "suddenly" cannot forward any attachments if they originated outside the Windows Domain. We have disabled his AVAST Antivirus Mail Shield, upgraded from Outlook 2007 to Outlook 2010, but with the same results. There are no errors in the Event Log. The error the User gets is "Cannot send this item." Once he closes the error dialog, it drops into his Drafts folder. The temporary Internet Files location for Outlook has been cleared, but he receives the same error.