In Firefox, you can change the default PDF render under Options > Applications > scroll down at the very bottom.
Click to open it and enable the setting “ Download PDF files instead of automatically opening them in Chrome”. Go to chrome://settings/content page, scroll down to the bottom of the page to find PDF documents section. Since the plugins page has been removed in Chrome version 57, here is how you can disable the default PDF viewer and use the native Acrobat PDF Reader to open and read PDF files. Also be sure to make sure Adobe Reader is enabled, or else you will have no plugin to view PDF documents in Chrome. Scroll down a little you will find Chrome PDF Viewer click disable to disable the built-in PDF render in Chrome. Head to chrome://plugins/ in Chrome, this will bring up the plugins page. Here is how, Change Default PDF Viewer in Chrome You can change the default built-in PDF viewer in Chrome or Firefox. Chrome and Firefox have already implemented its own PDF render engine within the browser, hence, such render does not support Adobe’s special interactive PDFs. With that, you need Adobe PDF reader to view them and save those fillable PDF forms. The default PDF Viewer can render pretty much all the PDF out there except … interactive PDF forms. Up until recently, I found no need to change the default PDF Viewer in Chrome or Firefox.
