No matter how many times I try to download a copy of a sent email as a PDF it comes through as a Firefox File or just "file". Neither can be opened in my computer.
Sorry to hear this. I tested this and was not able to reproduce the issue. Would you mind providing us with a screenshot of what you're seeing, along with the version of Firefox you are using so that we can take a closer look?
Also, is this issue happening in Firefox only, or other browsers as well?