This article will help you determine whether an extension, theme or hardware acceleration is causing your Firefox problem and, if so, describes what you can do to make Firefox run normally again.

Start Firefox in Troubleshoot Mode

Troubleshoot Mode temporarily disables all extensions, uses the default theme, and turns off hardware acceleration. Running Firefox in Troubleshoot Mode can help determine if one of these is causing your problem. To learn more, see Diagnose Firefox issues using Troubleshoot Mode. To start Firefox in Troubleshoot Mode:

1. Click the menu button , click Help, select Troubleshoot Mode… and click Restart in the Restart Firefox in Troubleshoot Mode? dialog.

   Note: You can also start Firefox in Troubleshoot 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).

   

2. When the Open Firefox in Troubleshoot Mode? window appears, click the Open button.

After you click the Open button and Firefox starts, test for your problem.

The problem still occurs in Troubleshoot Mode

If your problem persists in Troubleshoot Mode, it is not being caused by an extension, theme or hardware acceleration. Other possible causes include changes made to Firefox preference settings, which are not disabled in Troubleshoot Mode. For additional troubleshooting suggestions, see these articles:

• Troubleshoot and diagnose Firefox problems
• Reset Firefox preferences to troubleshoot and fix problems

The problem does not occur in Troubleshoot Mode

If your problem did not occur in Troubleshoot Mode, the likely cause is an extension, theme or hardware acceleration. Continue following the steps in this article to determine whether one of these is the problem.

Turn off hardware acceleration

With some graphics processors and graphics driver setups, Firefox may crash or have trouble showing text or objects on pages when using hardware acceleration. You can try turning off hardware acceleration to see if it fixes the problem.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the General panel.
3. Under Performance, uncheck Use recommended performance settings.
   Additional settings will be displayed.

   

4. Uncheck Use hardware acceleration when available.
5. Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
6. 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. Otherwise, your problem is likely related to extensions or themes. Continue with the steps in this article to see if they help.

Switch to the default theme

If you are using a theme other than the default Firefox theme:

1. Click the menu button , click Add-ons and themes and select Themes.
2. Find the System theme and click the Enable button to make Firefox switch to that theme.
3. Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
4. Start Firefox the way you normally do.

Test for your problem. If it no longer occurs, the theme you were using was causing it. If it still occurs, continue following the steps in this article.

Disable all extensions

To determine whether a faulty extension is causing your problem, you can disable all of your installed extensions:

1. Click the menu button , click Add-ons and themes and select Extensions.
2. For any extension listed as Enabled, click the blue toggle for the corresponding extension.

   The extension will be moved to the Disabled list.

3. Repeat this for each of the other extensions.
4. When all extensions are disabled, close Firefox: Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
5. Start Firefox the way you normally do.

Test for your problem. If the problem no longer occurs with all extensions disabled, one of your extensions was causing it. To find the extension that was causing your problem, continue as follows:

Test for faulty extensions

To determine which of your disabled extensions was causing your problem, you can re-enable each extension one at a time.

1. Click the menu button , click Add-ons and themes and select Extensions.
2. Click the corresponding toggle to enable the extension. The toggle turns blue when enabled.
3. Close Firefox: Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
4. Start Firefox the way you normally do.

After you restart Firefox, test for your problem. If the problem comes back, the extension you just enabled was causing it.

After you find the extension that was causing your problem, disable or uninstall the faulty extension and re-enable the other extensions in the Add-ons Manager.

Updating extensions

If an extension was causing your problem, it may have an update available that will fix it:

1. Click the menu button , click Add-ons and themes and select Extensions.
2. Click the gear button at the top of the Add-ons Manager and select Check for Updates.
3. If updates are found, install them by clicking Install Updates.
4. When the installation is complete, close Firefox: Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
5. Start Firefox the way you normally do.

After Firefox restarts, your extensions will be updated. If the extension that was causing your problem had an update, re-enable it and test for your problem again.

Checking extension settings

Some problems are caused if the settings of an extension override Firefox settings (e.g. problems with toolbars). Therefore you may want to check the extension's settings to see if you can find the option that is causing your problem:

1. Click the menu button , click Add-ons and themes and select Extensions.
2. For the extension that is causing your problem, click the ellipsis (3-dot) icon and click the OptionsPreferences button.
3. Click your way through the settings to see if there is an option that may solve your problem.
4. If you found a suitable option, click Save and then restart Firefox.