Thank you, Mahesh.
I took a few moments to try and replicate this behavior, but I was unable to. Here are the steps I took on my test installation running 15.2.6039:
- Logged in as the System Admin and managed a Domain.
- Impersonated a user to access their Junk Email folder.
- Checkmarked 4-10 messages and chose to Forward to send the EML files to the Domain Admin.
- Once in the Domain Admin's mailbox, I clicked Download All Attachments and opened the compressed file in Finder.
- I was able to open and view the contents for each file by choosing Open With > TextEdit.
- I also downloaded each file individually and was met with the same results.
I can also attempt to replicate this using the same browser you're in. Can you let me know which you've tried?
If I'm unable to replicate this, I would encourage you to submit a ticket to our Support Department so they can troubleshoot this directly. It may be a bug in the software; however, it could also be an issue specific to your installation. (In the case that this is a bug, your ticket would be refunded back to you.)