Attachment filename not en/de-coded correctly when longer than 13 characters

Question

I am using the following code to send an email attachment. I\'m using C#, .NET 4.0, BPOS Exchange server to send.

var message = new MailMessage(\"duncanba         


        

Answer 1

Turns out that this is a known issue, & Microsoft has issued a hotfix. See: An email message attachment name that contains non-ASCII characters and is longer than 41 UTF-8 encoded bytes is encoded two times before transmission in an application that is compiled for the .NET Framework 4.