hi hmoore234, starting from version 52 firefox will no longer support npapi plugins like communicated a while ago already: https://blog.mozilla.org/futurereleases/2015/10/08/npapi-plugins-in-firefox/

Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work?

A client of mine that is a fortune 500 company requires the plug-in for their file transfer site. Guess we will use Safari.

there's probably no technical necessity to implement that via a plugin instead of common "web-proof" methods. some legacy sites will have to adapt if they want to stay compatible with modern browsers like firefox, chrome or edge...

hmoore234 said

Media Shuttle Plug-In will not install in FIrefox 52.0b1 (64-bit). A client of mine that is a fortune 500 company requires the plug-in for their file transfer site. Guess we will use Safari.

Or you could use the 64-bit Firefox 51.0.1 Release www.mozilla.org/firefox/all/

Why be a Tester with the Beta builds of Firefox 52.0 if you want things to be stable and work?. The b1 on 52.0b1 means it is the first Beta build of 52.0

A version on Beta development channel can get say six to twelve builds or more as there were 14 Beta builds for 51.0 for example.

The future Firefox 52.0 ESR (Extended Support Release) based on then Firefox 52.0 Release will allow other Plugins to be used besides Flash Player. A version on the ESR channel generally get eight updates in line with a major Firefox Release and are only for security and allowed stability fixes.

Already switched back to 51.0