Troubleshooting
- Types of Accounts
- unable launch older version on profile
- Unable to access secure (HTTPS) sites in Firefox 43
- Unable to authenticate to SMTP server
- Unable to download attachments from Hotmail or Windows Live Mail
- Unable to download files in Windows 10 when Parental Controls are on
- Unable to download files when Parental Controls are on
- Unable to download or save files
- Unable to Download Updates for Accuweather or Wikipedia
- Unable to Download Updates for Accuweather or Wikipedia on ZTE Open
- Unable to Download Updates for System, Accuweather or Wikipedia
- Unable to import contacts from Facebook on ZTE Open from Ebay
- Unable to install add-ons
- Unable to install add-ons (extensions or themes)
- Unable to install add-ons (extensions or themes) in Thunderbird
- Unable to install add-ons (extensions or themes) in Thunderbird Redirect 1
- Unable to install add-ons or extensions
- Unable to install System Update on ZTE Open from Ebay
- Unable to log in to sites window.crypto.signText on Firefox
- Unable to log in to sites with signText on Firefox
- Unable to log in to websites that use signText on Firefox
- Unable to play videos from streaming services in Firefox
- Unable to scroll with arrow keys
- Unable to uninstall add-ons (extensions or themes)
- Unable to use profile when you launch an older version of Thunderbird
- Unblocking the Java plugin
- Understand unexpected script warnings in Firefox
- Unexpected installation error -203 when installing add-ons
- Uninstall BitGuard to fix crashes with Firefox
- Uninstall BitGuard to fix crashes with Firefox 25
- Uninstalling toolbars
- Unsafe properties of OpenPGP keys might be ignored
- Unsent crash reports in Firefox for Android
- Update Accuweather or Wikipedia
- Update for Accuweather or Wikipedia won't download on ZTE Open
- Updates reported when running newest version
- Updating processor microcode
- Use Internet Explorer messages upon Firefox startup
- Use MDN offline with your MDN Plus subscription
- userChrome.css and .js and userContent are unsupported
- Username and password not remembered
- Usernames and passwords are not saved
- Use the Troubleshooting Information page to help fix Firefox issues
- Use Troubleshoot Mode in Firefox
- Using a dedicated profile for Firefox Nightly
- Using OpenPGP secret keys that advertise features that are not supported by Thunderbird
- Using the RealPlayer plugin with Firefox
- Using the Troubleshooting Information page
- Video or audio does not play
- View articles recommended by Pocket on your Firefox for Desktop homepage
- Vine and other HTML5 videos won't play
- Warning Unresponsive plugin - What it means and how to fix it
- Warning Unresponsive script
- Warning Unresponsive script - What it means and how to fix it
- Webpages are large and blurry after updating Firefox - how to fix
- Web pages aren't displaying properly in Firefox for Android
- Website colors are wrong
- Websites don't load - troubleshoot and fix error messages
- Websites incorrectly report that Firefox is outdated or incompatible
- Websites look wrong
- Websites look wrong or appear differently than they should
- Websites or add-ons incorrectly report incompatible browser
- Websites say cookies are blocked
- Websites say cookies are blocked - Unblock them
- Websites say that Firefox is outdated or incompatible even though it's the latest version
- Websites show a spinning wheel and never finish loading
- Website will not allow Firefox to display the page if another site has embedded it
- What does "Your connection is not secure" mean?
- What do the security warning codes mean?
- What happened to Adaptive Search?
- What happened to Firefox Home?
- What happened to the Thunderbird File, Edit, and View menus?
- What happens when your SUMO profile is inactive or deleted
- What is Mozilla BadgeKit?
- What is the difference between Firefox Marketplace and Adaptive App Search?
- What is the different between Firefox Marketplace and Adaptive App Search?
- What is the winmail.dat attachment?
- What should I do if I'm redirected to the Firefox Relay FAQ when clicking a link within an email?
- What's new in Firefox for iOS (version 39)
- What's new in Firefox Klar for Android
- What's new in Firefox Klar for Android (version 93)
- What's new in Firefox Klar for iOS (version 106)
- What's new in Firefox Klar for iOS (version 107)
- What's new in Firefox Klar for iOS (version 40)
- What’s New with Colorways?
- What's the difference between MDN and MDN Plus?
- What to do if Firefox won't play any sounds
- What to do if you can't download or save files
- What to do when searches take you to the wrong search website
- Where can I go for technical help?
- Why aren’t my add-ons working on some websites?
- Why are some add-ons not allowed on sites restricted by Mozilla?
- Why can't Firefox for mobile play Flash on my device?
- Why can't I create a custom ringtone?
- Why can't I sync my passwords?
- Why can’t I use Firefox sync with my Google or Apple ID?
- Why does Monitor show me in a data breach for a site I never signed up to?
- Why does Mozilla disable some add-ons from running in Firefox?
- Why does Thunderbird warn me that my server doesn't use encryption?
- Why does Thunderbird warn me that my server don't use encryption?