Technical Support General

Mozilla Firefox Troubleshooting


Click to open each section for troubleshooting tips:

How to check browser version and/or update 
  1. In the upper right-hand corner of the browser window, select the three vertical lines.
  2. In the menu that opens, select “Help”.
  3. In the new menu that opens, select “About Firefox”.
    • A small pop up window will open that displays the version of Mozilla Firefox that is installed. Firefox will check and download updates automatically.
  4. When the download has completed, select “Restart to update Firefox” to begin using the updated version.
How to clear browser cache, cookies, and temporary internet files 

Cache is a place on your computer where active data is temporarily stored to shorten access times. In other words, cache keeps data that is frequently requested and accessed by the system. It is, therefore, saved in dedicated quick-to-access storage to reduce the time taken to retrieve the data. Results? Better latency and improved I/O (input/output). This has a direct impact on app performance, as most applications are dependent upon input and output operations.

Web Browser Cache In web browsers, for example, frequently visited webpages are cached to improve performance. To load a webpage, your browser will then be able to access locally stored data, instead of having to request it be sent again. To see cached data at work, try clicking “return” to go back to the previous page. Your browser will be able to recover most of the files it requires from the cache. It will also read cache at a far quicker rate than reading the files from the webpage again.

Why do you need to clear cache?

While cache is beneficial by design, it isn’t perfect. Its imperfections can lead to an opposite effect and cause issues with forms, logins or even entire webpage data. This happens when cached data gets outdated or altogether corrupted. The browser then wastes time trying to fetch corrupted data or reading an old item from the cache.

An immediate solution to the issue is to clear out the cache and let your browser rebuild a new one.

How do I clear my browser cache on a pc?

Quick Tip: With any browser open on your Windows operating system, press the following keys (simultaneously) to quickly access the options for clearing the browser’s history:


How do I clear my browser cache on a Mac?

Quick Tip: With any browser open on your Windows operating system, press the following keys (simultaneously) to quickly access the options for clearing the browser’s history:

  1. In the main menu of the browser, select History > Clear Recent History. Define the time range you want to delete. To delete all cache data, select Everything from the drop-down menu.
  2. Click on the arrow next to details to show the different possibilities of which data should be deleted. If you want to delete only cache, then only check Cache.
  3. Click the Clear now button.
  4. Reload the site afterwards.
Mozilla Firefox – To learn more about clearing your browsing history, cookies, and cache, visit Mozilla Firefox Support.
How to add a website as a trusted site 
What is Enhanced Tracking Protection when browsing 
Enhanced Tracking Protection in Firefox automatically protects your privacy while you browse. It blocks many of the trackers that follow you around online to collect information about your browsing habits and interests. It also includes protections against harmful scripts, such as malware that drains your battery.
Though these are invisible protections, you can see what’s being blocked on individual pages by clicking the shield to the left of the address bar.
To see what been blocked on all sites over the past week, click the menu button and select Privacy Protections. (Alternatively, you can enter ‘about:protections’ into the address bar.) This will open the Privacy Protections page in a new tab.
For further information on enhanced tracking protection and how to adjust settings, visit Mozilla Firefox Support.
Block or Allow pop-ups in Firefox 
What are pop-ups?
Pop-up windows, or pop-ups, are windows that appear automatically without your permission. They vary in size, but usually don’t cover the whole screen. Some pop-ups open on top of the current Firefox window, while others appear underneath Firefox (pop-unders).
Firefox allows you to control both pop-ups and pop-unders in Firefox Options. Pop-up blocking is turned on by default, so you don’t have to worry about enabling it to prevent pop-ups from appearing in Firefox.
Pop-up blocker settings
  1. On your computer, open Firefox.
  2. At the top right, click More and select options.
  3. Select the Privacy & Security panel.
  4. Under the Permissions section, uncheck the box next to Block pop-up windows to disable the pop-up blocker altogether.
  5. A click on Exceptions opens a dialog box with a list of sites that you want to allow displaying pop-ups.
  6. The dialog box offers you the following choices:
    • Allow: Click this to add a website to the exceptions list.
    • Remove Website: Click this to remove a website from the exceptions list.
    • Remove All Websites: Click this to remove all the websites in the exceptions list.
For additional information, please visit Mozilla Firefox Support.
Enable/Disable Cookies 
The process for enabling/disabling cookies in Mozilla Firefox is as follows:
Open the Mozilla Firefox browser.
  1. In the top right corner, click the menu icon – it looks like the three horizontal lines on top of each other.
  2. In the menu that opens, select Options.
  3. In the new tab that opens, click the Privacy & Security option.
  4. It will now display the browser privacy options which you have three to choose from: Standard, Strict, and Custom.
  • Standard: gives you reasonable privacy settings; it will allow normal “first-party” cookies that most websites rely on to work and will block “third-party” tracking cookies – which are often used by companies to track your behavior across multiple websites. It will also block known trackers used by invasive advertising companies only when you open a “Private” browser window. Cryptocurrency miners are also blocked by this setting.
  • Strict: gives you stronger privacy and security settings on the web; however it may cause some websites to not work properly. If this happens, it’s easy to white-list certain websites to disable the protection on sites you trust. Just like standard, it will block third-party tracking cookies (while still allowing first-party cookies which most websites need), and it also blocks Crypto miners. However, now it also blocks known trackers in all of your browser tabs/windows (instead of just when you’re in Private Browsing). It also blocks software that tries to “finger-print” your browsing set up in order to personally identify you.
  • Custom: gives you fine-grained control over what will be allowed/blocked by Firefox. You can choose to individually allow or block trackers, crypto miners, finger-printers and types of cookies. To block all third-party cookies with Firefox, choose the custom option and then for the Cookies item, select All third-party cookies (may cause websites to break).
Flash player 
Note: Adobe will end support of Flash Player on December 31, 2020. Flash support will be completely removed from consumer versions of Firefox in December 2020.
Firefox lets you choose whether to allow the plugin to run on a website, it is no longer on by default.
How to enable Flash Player while viewing a website:
If Firefox blocks a plugin, rather than seeing content you will see a message prompting you to click to run the plugin, such as Adobe Flash.
Alternatively, there may be a blank rectangle box, and the plugin notification icon will appear toward the left end of the address bar. If you click on the message or the notification to activate the plugin, Firefox will prompt you with these options:
  • Allow: Activates the plugin on the website, only for a single visit.
  • Don’t Allow: Dismisses the notification prompt without activating the plugin.


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