How do I disable the built in pdf viewer in Mozilla Firefox?
Follow these instructions to disable the built in PDF viewer in Mozilla Firefox.
In some cases you will need to disable the built in browser pdf viewer, to force documents from platforms such as smartforms to open in Acrobat rather than in the browser window.
1. In the address bar of Firefox, enter about:config
2. Agree to the screen which tells you that by going to config, you will void your Firefox warranty.
3. Find the entry for pdfjs.disabled and double click its name to change the value to TRUE