Firefox hangs or is not responding - How to fix
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- Revision id: 92052
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- Creator: AliceWyman
- Comment: Firefox hangs when you quit it: updated error for fx34
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- Reviewed by: AliceWyman
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When Firefox hangs, it stops responding to your clicks and keystrokes and doesn't seem to be doing anything. Also, a "(Not Responding)" label is displayed in the title bar and the mouse cursor becomes a spinning wheelhourglass when it's over the Firefox window.Also, the mouse becomes a spinning wait cursor when it's over the Firefox window. This article gives you solutions to Firefox hangs depending on when they happen.
- If Firefox uses a lot of computer resources, see the solutions proposed in Firefox uses too much memory or CPU resources - How to fix and Firefox uses too much memory or CPU resources - How to fix.
- If you get a "Warning: Unresponsive script" prompt, see Warning Unresponsive script - What it means and how to fix it.
- If Firefox closes unexpectedly, see Troubleshoot Firefox crashes (closing or quitting unexpectedly).
To resolve hanging problems not specifically mentioned in this article, or if the suggested solutions do not solve the problem, see Troubleshoot and diagnose Firefox problems.
Table of Contents
Firefox hangs at random times
If Firefox seems to hang randomly and not after a specific action (for example, downloading a file or quitting Firefox), try the solutions in this section.
Create a new places database
If hangs are periodic, it may be caused by a corrupted places database.
To create a new places database, do the following:
- The template "ProfileFolder" does not exist or has no approved revision.
- Click the Firefox menu and select .Click the Firefox menu at the top of the screen and select .Click the Firefox menu and select Wait until Firefox has completely quit. .
- In the Firefox profile folder, find and rename the files places.sqlite to places.sqlite.old and places.sqlite-journal to places.sqlite-journal.old (if it exists).
- To rename a file, right-click on it and select rename from the menuclick on it once to select it and then click a second time on the file name to make it editable. Then add .old to the end of its name.
- Finally, reopen Firefox.
- When Firefox reopens it will create a new places database. Your browsing history will be lost but Firefox will automatically import your bookmarks from the most recent backup file.
Turn off hardware acceleration
With some graphics card and graphics driver setups, Firefox may hang when using hardware acceleration. You can try turning off hardware acceleration to see if it fixes the problem.
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel and the tab.
- Uncheck Use hardware acceleration when available.
- Click the Firefox menu and select .Click the Firefox menu at the top of the screen and select .Click the Firefox menu and select .
- Start Firefox the way you normally do.
If the problem is no longer happening, then hardware acceleration was likely the cause. You can try updating your graphics drivers to see if that fixes it or simply run without hardware acceleration.
Troubleshoot your plugins
Sites that use plugins such as Java, Adobe Reader, or Flash can cause Firefox to hang. For information on troubleshooting plugins and on determining whether a plugin is causing your problem, see the Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems article.
Delete duplicated Session Restore files
Firefox may be slow to respond or hang if multiple copies of its Session Restore file have been created:
-
Open your profile folder:
- Click the menu button , click and select .From the The Troubleshooting Information tab will open. menu, select .
- Under the Application Basics section next to Profile FolderDirectory, click . A window will open that contains your profile folder.Your profile folder will open.
Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox. - Click the Firefox menu and select .Click the Firefox menu at the top of the screen and select .Click the Firefox menu and select .
- Locate and delete the sessionstore.js file and any copies, such as sessionstore-1.js, sessionstore-2.js.
Change the PAC implementation
If you're using a proxy auto-config file (PAC), Firefox may hang when you attempt to load sites that don't exist or that you haven't opened recently. To determine if you use an automatic proxy configuration file:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Click the icon.
- Click the tab.
- Click . The Connection Settings dialog appears.
- If Automatic proxy configuration URL is selected, you are using an automatic proxy configuration file. Do not disable this setting, which will prevent you from accessing the Internet. Instead, provide this workaround to your network administrator.
- Click .
Firefox hangs while playing Flash videos
See Playing Flash videos makes Firefox hang.
Firefox hangs after using it for a long time
Update Firefox
The latest Firefox versions includes improvements in memory usage, especially during long sessions. Update Firefox to the latest version.
Restart Firefox
Firefox may hang if left open for long periods of time. To fix the issue, restart Firefox.
If you regularly leave Firefox open so that you return to where you left off, you may want to use Firefox's Session Restore feature. For more information, see Configuring session restore.
Firefox hangs while loading the first window
Speed up Session Restore
If you have many tabs to restore, Firefox may hang while loading those sites. Make sure that Don't load tabs until selected is checked in the Tabs panel of the OptionsPreferences window so that only the last selected tab is loaded at startup. You can also try to use Tab Groups so that only websites in the visible tab group load first.
Firefox hangs when downloading files or saving images
If Firefox hangs when you attempt to download a file or save an image, try these solutions:
Clear download history
Firefox may hang when downloading files if your download history has grown too large. To clear the download history:
- At the top of the Firefox window, click on the button ( menu in Windows XP), and then click On the menu bar, click on the menu, and then click At the top of the Firefox window, click on the . The Downloads window will open. menu, and then click Click the Downloads button and then click . The Library window will open.
- Click . The download history is cleared.Click to delete the download history.
- Download some sample files to see if the hanging has stopped.
Choose a different download folder
Firefox may hang if the last download folder location (e.g. a shared volume or USB drive) is no longer available. To fix this:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- In the Downloads pane, select Save files to and click the button.
- In the Browse For Folder window, choose a new folder location.
- Close the page. Any changes you've made will automatically be saved.
See if you are now able to download files or save images. If this works, you can go back to your Firefox settings, if you wish, and select
.Disable virus scan in Firefox preferences
With some antivirus programs, the virus scan that Firefox starts after files are downloaded may cause Firefox to hang. You can disable virus scanning with the following steps (this will not disable your antivirus program):
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - Locate the browser.download.manager.scanWhenDone preference and double click it to change the value to false.
Firefox hangs when you quit it
Sometimes when you close Firefox, it may stop responding and remain in memory, even though no Firefox windows are open. This can prevent Firefox from working properly the next time you open it or you may see a "Close Firefox" dialog box with the message, Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.The old Firefox process must be closed to open a new window. You must then end all Firefox processes or restart the computer before you can reopen Firefox (see "Firefox is already running but is not responding" error - How to fix for other causes and solutions).
Close Firefox completely
- Click the Firefox menu and select .Click the Firefox menu at the top of the screen and select .Click the Firefox menu and select .
- Close any remaining dialog boxes or secondary windows such as the Downloads window.
If Firefox processes that remain in memory at exit are a recurring problem, try the following solutions.
Troubleshoot your extensions
A problematic extension can cause the problem, which can be resolved by disabling or uninstalling the extension. For information on diagnosing and fixing problems caused by faulty extensions, see the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article.
Update or disable the Java plugin
Sometimes Java applets can cause the Firefox process to persist after exit. Try updating Java to the latest version by going to Mozilla's plugin check page or, if you don't need the Java plugin, you can disable it from the Plugins panel of the Firefox Add-ons Manager. For more information, see Use the Java plugin to view interactive content on websites.
Troubleshoot your Internet security software
Interactions between certain Internet security software (firewall, anti-virus software) is reported to cause hangs on some systems. You can try to configure your firewall to see if it helps the hang go away.
Based on information from Firefox hangs (mozillaZine KB)