Hi lnagel, is this problem still continuing? I haven't seen any other WIX threads, so I'm not sure whether this affects all stores or there is something particular to yours. Is WIX able to diagnose the issue?

Here is a known issue which is not related to recent updates:

Servers can send a download with a header like this:

Content-Disposition: attachment; filename="My First Novel.pdf"

If the quotation marks are omitted, however, Firefox truncates the file name at the first space, and the user will get a file named My which obviously not what you want.

The workaround, if you don't control the Content-Disposition header, is to replace any spaces in the file name with a character, such as an underscore.

Please provide a public link (no password) that we can check out. No Personal Information Please !

Yes that is the problem exactly - FYI - WIX has responded that they do not support Firefox and suggested Chrome or IE browsers. Unfortunately the exact filename (with spaces) is important to my user's DL so I'm still kinda stuck. My alternative temp solution was to post a notice on my website stating that it is best viewed in browsers other than FF. Thanks for the response

I'm surprised WIX has this bug in their code. It is not a new issue, as Mozilla has stubborn stuck to this standard requirement since Firefox was initially launched.

https://tools.ietf.org/html/rfc6266#appendix-D