I found this great link to help open email attachments:
It doesn’t happen often, but every once in a while, someone will send me an email attachment. It is either a file that ends with “.eml” or a winmail.dat file. GMail can’t open those attachments; it has a “View” link but that just shows the raw text that can be very hard to read. Now, I can use this tool.
The tool says that you can “Upload and View a .EML, .MSG or winmail.dat message”. I haven’t used it a lot, but it has worked for me so far. The only problem that I have had is that I haven’t gotten winmail.dat files to work yet: