Whenever we have attachments of type EmbeddedItem(like Msgs that came as attachment), we get a bad attachment for the Msg-Attachment.
We are using this method for saving the Msg file with EntryIds
using (FileStream fs = File.OpenWrite(physicalFilePath))
We have seen related issues being worked
with resolutions here;
I guess these updates have fixed the issue with Aspose.Email.Mapi.MapiMessage.
But we still have this issue when using SaveMessageToStream from PersonalStorage object.
I can attach a sample PST with just one email just so that you can reproduce it.