How to Fix Firefox Not Responding on PC and Mac

If these don’t work, scan for malware

Mozilla Firefox has been around for almost two decades, with numerous stability and performance enhancements. However, it’s still not uncommon to encounter instances with the browser freezing right after launch, during routine use, or while performing specific activities.

If you’re having trouble with Firefox not responding on your PC or Mac, go through the fixes below to troubleshoot and resolve the issue.

Restart Firefox

If Firefox just froze on your PC or Mac, try force-quitting and relaunching it. To shut down the browser on PC, right-click theStartbutton and chooseTask Manager. Then, chooseFirefoxfrom the list of open apps and selectEnd task. Relaunch the browser after that.

Open theLaunchpadand selectOther>Activity Monitorif you use a Mac. Then, selectFirefox>Stop>Force-Quitand attempt to start Firefox again.

Restart Your Computer

It’s best to restart your computer if Firefox continues to freeze. In Windows, just open theStart menuand selectPower>Restart.

On the Mac, open theApple menuand selectRestart, but clear the box next toReopen windows when logging back inbefore selectingRestartagain on the confirmation dialog.

Recreate the Places Database

Firefox stores your browsing history and bookmarks in a database called “Places.” Sometimes, it can corrupt and result in the web browser not responding. To rule that out, you must force Firefox to recreate the database.

Select theFirefox menuicon (the button with three stacked lines at the top right corner of the window) and chooseHelp>More troubleshooting information. Then, under theApplication Basicssection, select theOpen Folderbutton next toProfile Folder.

On the File Explorer or Finder window that subsequently shows up, open your Firefox profile folder and rename the files below by adding.oldto the end of the file name:

places.sqlite

places.sqlite-journal

If Firefox is completely unresponsive, you can directly get to the profile folder via File Explorer or Finder.

Windows: OpenFile Explorer, copy and paste the following path into the address bar at the top of the window, and pressEnter:

%userprofile%AppDataRoamingMozillaFirefoxProfiles

Mac: OpenFinderand selectGo>Go to Folder. Then, copy and paste the following path and pressEnter:

~/Library/Application Support/Firefox/Profiles

Update to Fix Firefox

Mozilla releases frequent updates to address known issues in Firefox. To check if the browser is up-to-date, open theFirefox menuand selectSettings. Then, under theGeneraltab, scroll down to theFirefox Updatessection and chooseCheck for updates.

Disable Hardware Acceleration

By default, Firefox takes advantage of the graphics processing unit (GPU) on your computer to improve web page functionality and performance. However, depending on your PC or Mac configuration, that could have the opposite effect. Disablehardware accelerationand check if that makes a difference.

Again, open theSettingspane inFirefoxand scroll down to thePerformancesection. Then, uncheck the boxes next toUse recommended performance settingsandUse hardware acceleration when available.

If that helps, consider updating the graphics drivers or the operating system (more on that next) before reactivating hardware acceleration again.

Update the Operating System

Running an up-to-date version of the operating system could positively impact how Firefox runs on your computer. To update Microsoft Windows 10/11, open theSettingsapp and selectWindows Update. Then, chooseCheck for updates>Download and install.

On the Mac, open theSystem Preferencesapp and selectSoftware Update>Update Now. Or, open theApple menuand chooseAbout This Mac>Software Update>Update Now.

Clear the Firefox Cache

Anobsolete local web cacheis another reason forperformance degradation in Firefox. Delete it to force the browser to fetch up-to-date site data.

To do that, go to Firefox’sSettingspane and switch to thePrivacy & Securitytab. Then, scroll down to theCookies and Site Datasection, selectClear Data, mark the boxes next toCookies and Site DataandCached Web Content, and selectClear.

Clear Firefox’s Startup Cache

If the Firefox browser tends to freeze at launch, you must clear its startup cache. Start by opening theFirefox menu. Next, go toHelp>Moretroubleshooting informationand selectClear startup cache.

If you have trouble visiting the screen above, you must refresh Firefox (more on that further below).

Clear Firefox’s Download History

Does Firefox only freeze while saving files offline? An extensive download history can cause that. To clear it, open theFirefox menuand selectDownloads>Clear Downloads.

Change the Firefox Downloads Folder

If Firefox stops responding whenever you initiate a download, try changing the folder where the browser saves files by default.

Open theSettingspane, scroll down to theDownloadssub-section, and use theBrowsebutton to switch to a different location. Avoid removable media for best results.

Open Firefox in Troubleshoot Mode

Firefox’s Troubleshoot Mode (formerly called Safe Mode) loads the browser with all customizations and add-ons disabled. That helps you determine if a third-party theme or extension is the source of the issue.

First, close Firefox. Next, hold down theShift(PC) orOption(Mac) key and relaunch the browser. On the pop-up window that shows, selectOpento open Firefox in Troubleshoot Mode.

If Firefox works OK in Troubleshoot Mode, open theFirefox menuand selectAdd-ons and Themes. Then, dig into theExtensions,Themes, andPluginscategories and perform the following:

Refresh Firefox

If none of the fixes above help, try refreshing Firefox. That removes all customizations and extensions and resets the browser to factory defaults. To do that, open theFirefox menuand selectHelp>More troubleshooting information. Then, chooseRefresh Firefox.

Alternatively, open Firefox while holding down theShift(PC) orOption(Mac)keys and selectRefresh Firefox.

Set Up a New Firefox Profile

To rule out issues with a corrupt Firefox profile, open the Firefox Profile Manager, selectCreate Profile, and set up a new user profile. If Firefox no longer freezes or crashes after that, you may want tomigrate the profile data from your old profile.

To access the Firefox Profile Manager, perform the following on your PC or Mac. If Firefox is already running, close it before you begin.

Windows: Right-click theStartbutton, selectRun, and execute the following:

firefox.exe -P

Mac: Open theLaunchpadand selectOther>Terminal. Then, run the following command:

/Applications/Firefox.app/Contents/MacOS/firefox-bin -P

Reinstall Firefox

It’s likely you’re dealing with a corrupt Firefox installation that only a complete reinstallation can fix. To remove Firefox on the PC, right-click theStartbutton, chooseApps and Featuresand selectFirefox>Uninstall. Just dragFirefoxfrom theApplicationsfolder into theTrashif you use a Mac.

After uninstalling Firefox, restart your computer. Then, download and install the latest version of the browser fromMozilla.com.

Don’t Discount Malware

If Firefox freezes occasionally or all the time despite performing the above fixes, you may be dealing with a malware infestation. Use thesetop antivirus utilities for the PCand Mac to perform a comprehensive scan for computer viruses.

Dilum Senevirathne is a freelance tech writer and blogger with three years of experience writing for online technology publications. He specializes in topics related to iOS, iPadOS, macOS, and Google web apps. When he isn’t hammering away at his Magic Keyboard, you can catch him binge-watching productivity hacks on YouTube.Read Dilum’s Full Bio

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