Troubleshoot and diagnose Firefox problems
Most problems with Firefox can be fixed by following the troubleshooting methods described below. Try these steps in order. If one doesn't work, move on to the next one. If you need extra help with any of this, we have a community of volunteers standing by.
Table of Contents
- 1 1. Restart your computer
- 2 2. Clear your cookies and cache
- 3 3. Restart Firefox in Safe Mode
- 4 4. Troubleshoot your plugins
- 5 5. Reinstall Firefox
- 6 6. Reset Firefox
- 7 1. Restart your computer
- 8 2. Clear your cookies and cache
- 9 3. Restart Firefox in Safe Mode
- 10 4. Troubleshoot your plugins
- 11 5. Reset your Firefox settings
- 12 6. Reinstall Firefox
- 13 7. Make a new profile
- 14 Other solutions
1. Restart your computer
Sometimes problems can be fixed by simply restarting your computer and then starting Firefox again.
2. Clear your cookies and cache
Many problems with loading web pages can be resolved by clearing Firefox's cookies and cache:
- At the top of the Firefox window, click on the button, go over to the menu and select .On the menu bar, click on the menu, and select .At the top of the Firefox window, click on the menu, and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
- At the top of the Firefox window, click on the button, go over to the menu and select .On the menu bar, click on the menu, and select .At the top of the Firefox window, click on the menu, and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
- Click the menu button
, choose and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
3. Restart Firefox in Safe Mode
Safe Mode is a troubleshooting mode that disables all extensions, uses the default theme, turns off hardware acceleration, and uses default toolbar settings and controls, among other things. To start Firefox in Safe Mode:
- At the top of the Firefox window, click the button, go over to the menuOn the menu bar, click the menuAt the top of the Firefox window, click the menu and select . Firefox will start up with the Firefox Safe Mode dialog.Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:
firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox)Click the menu button
, click help
and select . Firefox will start up with the Firefox Safe Mode dialog. Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox) - In the Firefox Safe Mode dialog, click .
- Check whether your problem is still happening while in Safe Mode.
- If the problem still happens in Safe Mode, go on to step 4.
- If the problem does not happen in Safe Mode, see the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article and follow the instructions under The problem does not occur in Safe Mode to narrow down the cause.
4. Troubleshoot your plugins
Sometimes plugins for Firefox (such as Adobe Reader, Flash, Java, QuickTime, RealPlayer, and Windows Media Player) can cause problems that may be fixed in the latest version. To check to see if you have the latest versions of all your plugins, go to our Plugin Check page If any of your plugins are out of date, click and follow the instructions for updating that plugin. After you've updated all of your plugins, restart Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
-
At the top of the Firefox window, click on the buttonOn the menu bar, click on the menuAt the top of the Firefox window, click on the menu, and then click . The Add-ons Manager tab will open. Click the menu button
and choose . The Add-ons Manager tab will open.
- In the Add-ons Manager tab, select the panel.In the Add-ons Manager tab, select the panel.
- Click each plugin in the list and then click .
- Check whether your problem happens when you have all plugins disabled.
-
At the top of the Firefox window, click on the buttonOn the menu bar, click on the menuAt the top of the Firefox window, click on the menu, and then click . The Add-ons Manager tab will open. Click the menu button
and choose . The Add-ons Manager tab will open.
- In the Add-ons Manager tab, select the panel.In the Add-ons Manager tab, select the panel.
- Click each plugin in the list and then select in its drop-down menu.
- Check whether your problem happens when you have all plugins disabled.
If your problem goes away when all of your plugins are disabled, see the Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems article to learn how to narrow down which one is causing it.
5. Reinstall Firefox
Some Firefox issues can be caused by a problem with one of the Firefox program files. Follow these steps to completely remove and reinstall Firefox.
- Download the latest official version of Firefox from mozilla.org.
- Exit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Delete the Firefox installation folder, which is located in one of these locations, by default:
- (32-bit Windows) C:\Program Files\Mozilla Firefox
- (64-bit Windows) C:\Program Files (x86)\Mozilla Firefox
- Reinstall Firefox - see How to download and install Firefox on Windows for instructions.
- Download the latest official version of Firefox from mozilla.org.
- Quit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Uninstall Firefox by opening the Applications folder in the Finder and dragging the Firefox application to the Trash.
- Reinstall Firefox - see How to download and install Firefox on Mac for instructions.
- Download the latest official version of Firefox from mozilla.org.
- Quit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Uninstall Firefox - If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux for details. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory to uninstall Firefox.
- Reinstall Firefox - see Install Firefox on Linux for instructions.
Now start Firefox and check to see if your problem has been fixed. If it has, you can reinstall the extensions and themes you verified (in part 3 above) were not causing problems. If your problem hasn't been fixed continue with the next troubleshooting method.
6. Reset Firefox
The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information.
- At the top of the Firefox window, click the menu and select .At the top of the Firefox window, click the button, go over to the sub-menu and select .On the menu bar, click the menu and select .
-
- If you're unable to access the menu, type about:support in your address bar to bring up the Troubleshooting information page.
-
- Click the button in the upper-right corner of the Troubleshooting Information page.
-
- To continue, click in the confirmation window that opens.To continue, click in the confirmation sheet that slides down.
- Firefox will close and be reset. When it's done, a window will list the information that was imported. Click and Firefox will open.Firefox will close and be reset. When it's done, a window will list the information that was imported. Click and Firefox will open.
- Click the menu button
and then click help
.
- From the menu choose .
- If you're unable to access the menu, type about:support in your address bar to bring up the Troubleshooting information page.
- Click the button in the upper-right corner of the Troubleshooting Information page.
-
- To continue, click in the confirmation window that opens.
- Firefox will close and be reset. When it's done, a window will list the information that was imported. Click and Firefox will open.
1. Restart your computer
Sometimes problems can be fixed by simply restarting your computer and then starting Firefox again.
2. Clear your cookies and cache
Many problems with loading web pages can be resolved by clearing Firefox's cookies and cache:
- At the top of the Firefox window, click on the button, go over to the menu and select .On the menu bar, click on the menu, and select .At the top of the Firefox window, click on the menu, and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
- At the top of the Firefox window, click on the button, go over to the menu and select .On the menu bar, click on the menu, and select .At the top of the Firefox window, click on the menu, and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
- Click the menu button
, choose and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click .
3. Restart Firefox in Safe Mode
Safe Mode is a troubleshooting mode that disables all extensions, uses the default theme, turns off hardware acceleration, and uses default toolbar settings and controls, among other things. To start Firefox in Safe Mode:
- At the top of the Firefox window, click the button, go over to the menuOn the menu bar, click the menuAt the top of the Firefox window, click the menu and select . Firefox will start up with the Firefox Safe Mode dialog.Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:
firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox)Click the menu button
, click help
and select . Firefox will start up with the Firefox Safe Mode dialog. Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox) - In the Firefox Safe Mode dialog, click .
- Check whether your problem is still happening while in Safe Mode.
- If the problem still happens in Safe Mode, go on to step 4.
- If the problem does not happen in Safe Mode, see the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article and follow the instructions under The problem does not occur in Safe Mode to narrow down the cause.
4. Troubleshoot your plugins
Sometimes plugins for Firefox (such as Adobe Reader, Flash, Java, QuickTime, RealPlayer, and Windows Media Player) can cause problems that may be fixed in the latest version. To check to see if you have the latest versions of all your plugins, go to our Plugin Check page If any of your plugins are out of date, click and follow the instructions for updating that plugin. After you've updated all of your plugins, restart Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
-
At the top of the Firefox window, click on the buttonOn the menu bar, click on the menuAt the top of the Firefox window, click on the menu, and then click . The Add-ons Manager tab will open. Click the menu button
and choose . The Add-ons Manager tab will open.
- In the Add-ons Manager tab, select the panel.In the Add-ons Manager tab, select the panel.
- Click each plugin in the list and then click .
- Check whether your problem happens when you have all plugins disabled.
If your problem goes away when all of your plugins are disabled, see the Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems article to learn how to narrow down which one is causing it.
5. Reset your Firefox settings
Some problems can be fixed by resetting your Firefox preference settings:
- At the top of the Firefox window, click the button, go over to the menuOn the menu bar, click the menuAt the top of the Firefox window, click the menu and select . Firefox will start up with the Firefox Safe Mode dialog.Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:
firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox)Click the menu button
, click help
and select . Firefox will start up with the Firefox Safe Mode dialog. Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running:firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox) - In the Firefox Safe Mode dialog, click to put a check mark by Reset all user preferences to Firefox defaults.
- To apply your changes, click .
6. Reinstall Firefox
Some Firefox issues can be caused by a problem with one of the Firefox program files. Follow these steps to completely remove and reinstall Firefox.
- Download the latest official version of Firefox from mozilla.org.
- Exit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Delete the Firefox installation folder which is located here by default:
- (32-bit Windows) C:\Program Files\Mozilla Firefox
- (64-bit Windows) C:\Program Files (x86)\Mozilla Firefox
- Reinstall Firefox - see How to download and install Firefox on Windows for instructions.
- Download the latest official version of Firefox from mozilla.org.
- Quit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Uninstall Firefox by opening the Applications folder in the Finder and dragging the Firefox application to the Trash.
- Reinstall Firefox - see How to download and install Firefox on Mac for instructions.
- Download the latest official version of Firefox from mozilla.org.
- Quit Firefox:
At the top of the Firefox window, click on the button and then select At the top of the Firefox window, click on the menu and then select On the menu bar, click on the menu and select At the top of the Firefox window, click on the menu and select
Click the menu button
and then click ExitQuit
- Uninstall Firefox - If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux for details. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory to uninstall Firefox.
- Reinstall Firefox - see Install Firefox on Linux for instructions.
Now start Firefox and check to see if your problem has been fixed. If it has, you can reinstall the extensions and themes you verified (in part 3 above) were not causing problems. If your problem hasn't been fixed continue with the next troubleshooting method.
7. Make a new profile
A bad profile can cause all kinds of problems with Firefox. To see whether your problem is caused by a bad profile, make a new one. If that fixes the problem, you can copy your data (bookmarks, saved passwords, etc.) over to the new profile.
- Use the instructions in the Use the Profile Manager to create and remove Firefox profiles article to start the Profile Manager and create a new profile.When creating a new profile, do not delete your old profile. You will lose all of your bookmarks, history, passwords and settings.
- Once you've created a new profile, select it in the Profile Manager and click .
Test to see if your problem occurs with the new profile. If it doesn't, you can copy your data to the new profile - see Recovering important data from an old profile for instructions.
Other solutions
If you've tried all of these troubleshooting methods and you're still having problems the issue may be with other software or hardware.
Check for conflicts with your Internet security software
Some Internet security software (including antivirus, antispyware, and firewall programs) can cause problems with Firefox including blocking it from opening websites, crashes, and more. Often you can open the program's settings, remove Firefox from its list of allowed or trusted programs and it will be re-detected and things should start working again. If your program is listed at the Configure firewalls so that Firefox can access the Internet article, you can get specific instructions for how to properly reconfigure it.
Scan your system for viruses and spyware
Periodically, you should scan your system for viruses, spyware, or other malware. These free malware removal tools are often useful:
If you need more help removing malware, see Troubleshoot Firefox issues caused by malware.
Check your hard drive and RAM for errors
A problem with your computer's hard drive or RAM may prevent Firefox from running or make it crash repeatedly. Here are instructions or tools for checking:
- your hard drive: How to perform disk error checking in Windows XP on microsoft.com
- your hard drive: Check a drive for errors on microsoft.com
- your hard drive: Improve performance by optimizing your hard drive - To repair a drive on microsoft.com
- your hard drive: Using Disk Utility to verify or repair disks on apple.com
- your hard drive: Testing a drive with Smartmontools on ubuntu.com
- your RAM: Memtest86+Rember
Based on information from Standard diagnostic - Firefox (mozillaZine KB)
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