I understand that Macs cannot open .msg email files? The Internets tell me to get a third-party app to do it. Any suggestions for a good app that doesn't come with spyware, etc?
Learn about .MSG files and view a list of programs that open them.
fileinfo.com
Here's something else you could try (no promises).
1. You need to have the icon for Apple's TextEdit in your dock.
2. Have the .msg file on the desktop
3. Drag-n-drop the .msg file onto the TextEdit icon in the dock
4. Does it open?
Even if it does, there may be a lot of "garbage/formatting" characters, but the core text of the message may still be readable.