I have tried the scenario using following code and observed that no extra space is added in the resultant MSG file. Give a try to the sample code using the attached .doc file and share the feedback. Please ensure that you use latest library Aspose.Email for .NET 17.2.0 in your testing. If issue is not resolved, share your sample code and .doc file for our testing here.
string dataDir = @"";
// Load a Word document from disk and save to stream as MHTML
Aspose.Words.Document wordDocument = new Aspose.Words.Document(dataDir + "Test.doc")
MemoryStream mhtmlStream = new MemoryStream();
wordDocument.Save(mhtmlStream, Aspose.Words.SaveFormat.Mhtml);
// Load the MHTML in MailMessage
mhtmlStream.Position = 0;
MailMessage message = MailMessage.Load(mhtmlStream, new MhtmlLoadOptions());
message.Subject = "Sending Invoice in Email";
message.From = "sender@gmail.com";
message.To = "recipient@gmail.com";
// Save the message in MSG format to disk
message.Save(dataDir + "WordDocAsEmailBody_out.msg", Aspose.Email.Mail.SaveOptions.DefaultMsgUnicode);
Thanks for the help, it seems the issue is not with Aspose. Utilizing your snippet of code in a small console application, links looked like they should, however implementing it in our solution did not help. It did however clarify that it is later parts of the application that introduces the error.