If you have recently upgraded the Firefox browser and it may not display pdf files correctly within the browser. To work around the problem make the following changes in your Firefox preferences:
- Open Firefox and click on the hamburger symbol (3 short horizontal lines at the top right-hand corner of the browser)
- Select Preferences
- Click on “General” option on the left-hand side of the browser.
- Scroll down the page until you find a heading “Applications”
- Scroll down the list of applications until you find “Portable Document Format”
- Click on the entry in the Action column
- A drop-down list of options will appear
- Select “Use system default application”
- Close preferences
You should now be able to display pdf files correctly in the Firefox browser.