Hi Alex Shloma,
Thank you for contacting Aspose support team again.
I have analyzed your requirements and observed that MailMessageLoadOptions is not used in the code. Please use following sample code to load the sample EMLs like “message.eml”, “RTF_body.eml” and “messageWithDocx.eml”.
new Aspose.Email.License().SetLicense(@"");
MailMessageLoadOptions loadOptions = new MailMessageLoadOptions();
loadOptions.FileCompatibilityMode = FileCompatibilityMode.PreserveTnefAttachments;
loadOptions.MessageFormat = MessageFormat.Eml;
var main = MailMessage.Load(@“RTF_body.eml”, loadOptions);
main.Save(@“RTF_body_saved_PreserveTnefAttachments.eml”, FileCompatibilityMode.PreserveTnefAttachments);
main.Save(@“RTF_body_saved_EmlFormat.eml”, MailMessageSaveType.EmlFormat);
It will address all your concerns in the above two threads accept changing the attachment name. Could you please try removing the attachment before changing the attachment name and then add it again with new attachment name?
Please feel free to write us back if you have any other query in this regard.