The next time you click on a link to download a PDF file, Firefox will show you a prompt asking what to do with the file. If you want Firefox to always ask you what to do with PDF files, follow the above steps to change the action for the Portable Document Format (PDF) entry, except select Always ask from the drop-down menu. Set Firefox to ask you what to do with PDF files
Note: When Open in Firefox is the selected action, the built-in PDF viewer is used.
Click on the context menu item for the system default PDF viewer (for example, click on Open in Adobe Acrobat Reader DC) (for example, click on Open in Preview) to open the PDF file in that application. On the download entry for the PDF file you want to open. Right-click Hold down the control key while you click. (Alternatively, open the Downloads Library window.) Open the Downloads panel by clicking the download icon next to the address bar. When Firefox is set as the default PDF viewer and you download a PDF file in Firefox and save it to your computer, you can use a different application to view those PDF files by following these steps: Use a different PDF viewer for downloaded PDF files When you're viewing a PDF file in Firefox, you can use the download button in the PDF viewer's toolbar to download and save the PDF file to your computer. The built-in PDF viewer will open the PDF file in Firefox without saving it. (To learn more about the built-in viewer, see Using Firefox's built-in PDF viewer, below.) When you click on a link to a PDF file or open it from the Firefox Downloads panel, it will be rendered with the built-in PDF viewer. The built-in viewer is used when Portable Document Format (PDF) files are set to Open in Firefox in your Firefox settings for different types of files.
3.5 Troubleshoot problems with the PDF viewerįirefox's built-in PDF viewer allows you to view almost all PDF files found on the web without an external application (exceptions to this are PDF files with a MIME type incorrectly set). 2.2 Set Firefox to ask you what to do with PDF files. 2.1 Disable the built-in PDF viewer and use another viewer. 2 Choose another PDF viewer to use by default or set Firefox to always ask. 1.1 Use a different PDF viewer for downloaded PDF files.