microsoft
.msg files with PR_MESSAGE_CLASS_W = REPORT.IPM.Note.NDR are not converted to .eml
I can successfully convert some .msg files to .eml, but one .msg file I cannot. It's a delivery notification that has PR_MESSAGE_CLASS_W = REPORT.IPM.Note.NDR. No .eml file is generated if I try to convert this one. I might share that file privately on request.
There’s no mime equivalent to convert to. Why do you want an eml for this message?
To be completely honest: I had no idea there was a functional difference between msg and eml. I had this msg file that does not show any "internet headers" in Outlook. I remembered eml is plain text, so I googled "convert eml to msg", found https://superuser.com/a/799994/253137, and tried it. Looking at the headers in MFCMAPI, I understand that the information I was looking for is simply not there. But I'd definitely like MFCMAPI to tell me at least something in this direction instead of silently just not creating the eml file. (My first reaction was, well, another example of poorly maintained OSS, just delete it. Luckily I did not!)
The EML conversion code is getting functionally less useful with the rise of 365, since o365 builds of office (IE, click to run) do not support the underlying API. As for silent failure - I would bet we never got an error back so we had no error to display. If I get bored I might set up an MSI box and debug it (NDR are easy to find - no need to share one).