Save Email as MSG file without using Outlook (COM object, etc.) or 3rd party software

Question

Right now, I'm using the Exchange Web Services API with PowerShell to pull down specific emails from exchange and save them as EML files. This works great; however, the user/customer requires the emails to be in msg format. There are two ways that I've seen to do this:

• Use Outlook/Outlook COM Object
• Use a 3rd party library or software (like this: http://www.independentsoft.de/exchangewebservices/tutorial/downloadmessagetomsgfile.html)

Are there any other alternatives? I would like to stick with PowerShell if possible, but it seems like EWS might be limited to writing EML files.

There is no flexibility on the MSG vs EML requirement (compliance).

EDIT: This will be run on a server; so I would prefer if this could be done without having Outlook installed.

Answer 1

You can still use PowerShell with the Outlook Object Model (OOM), if that's what you are hoping for.

You can also use Redemption, which has more features than OOM (it can also be run in a service, doesn't fire Outlook security prompts, etc.).

Answer 2

You can create an MSG file explicitly in your code (it is an OLE storage (IStorage) file and its format is documented) - parse the EML file, then populate various MAPI properties in the MSG file.

You can also use Redemption. Converting an EML file to MSG is as easy as

  RDOSession Session = new RDOSession();
  RDOMail Msg = Session.CreateMessageFromMsgFile(@"c:\temp\YourMsgFile.msg");
  Msg.Import(@"c:\temp\YourEmlFile.eml", rdoSaveAsType.olRFC822);
  Msg.Save();