Issues with Firefox

This list of the more frequently-encountered issues or problems with Firefox is organized by subject and may include links to MozillaZine forum topics and other external sources in addition to Knowledge Base articles. It is not a complete list of Firefox issues. If you don't find an answer below, you can browse all articles in the Category:Issues (Firefox), use the Knowledge Base Search function, or look through the official list of known issues found in the Firefox release notes.

General

• Browser will not start up
• Error loading websites
• Problems printing web pages
• Firefox says my profile is in use or that it is "already running but is not responding"
• All my bookmarks are gone or I can't save new bookmarks
• Firefox hangs, freezes or stops responding
• Firefox CPU usage
• Firefox crashes (an error occurs and Firefox closes)
• Reducing Firefox memory usage ("memory leak")
• Standard diagnostic steps when Firefox is no longer working properly

Installation and updates

• Problems with Firewalls after updating Firefox
• Firefox 2 not working after upgrade including broken tabs or missing bookmarks.
• Unable to install themes or extensions
• Problematic extensions (including those that cause conflicts with other extensions or plugins)
• Problems with extensions and themes after updating Firefox.
• Problems uninstalling extensions and removing "*.xpi" or "ghost" entries from the Extensions list
• Your Linux distributor releases a patched Firefox but the Firefox website wants to force you to update

User interface

• Clipboard (cut/copy/paste) not working.
• Can't scroll through webpages using the keyboard arrow keys (caret browsing issue)
• Find bar opens when typing in textbox
• Window shakes
• Resizing an oversized window or setting Firefox to allow resizing of popup windows
• Large gray bar or box below the status bar
• Unable to search or add new engines
• Toolbar customizations reset on startup (and other localstore.rdf issues).

Downloading opening or saving files

• Unable to save or download files (including "downloads.rdf" issue)
• "Object has been blocked" message when trying to download certain types of files (firewall issue)
• Download error: "The associated helper application does not exist" when trying to open certain files
• The Download Actions list is empty. More information here. (Bittorrent and "mimeTypes.rdf" issues)
• Changing media handling behaviour when clicking links to download or open certain types of files
• Opening files using plugins
• Firefox does not offer the option to "Do this automatically" or only "Save File" is offered when opening certain file types.
• Other Firefox file-opening and download issues

Problems with specific websites or web features

• Websites look wrong
• Images or animations don't load (or images look wrong)
• Quicktime symbol with a question mark replaces Flash content
• Video or audio doesn't play
• Background music doesn't play
• Unresponsive Script Error
• Popups not blocked (Details here)
• How to disable bookmark this page popup
• Why "ALT" text image tooltips don't work in Firefox. (Details here)

Privacy and security

• Websites report cookies are disabled when they're not
• User name and password not remembered
• "SSL is disabled" or "Could not initialize the browser's security component" error message.
• Links to local pages don't work
• Firefox asks for a nonexistent master password
• "Access to the port number given has been disabled for security reasons."

Other

• File associations or filetype icons are wrong after uninstalling Firefox
• "Failed to save the preferences file" error or changes to preferences not saved
• Determining whether Firefox problems are caused by issues related to plugins
• Firefox.exe always open in the Windows Task Manager and automatically loads on Windows boot up (malware issue)
• “XP Com: Event Receiver” Windows shutdown error caused by non-responding firefox process (bug 309150)

See also

Firefox FAQs