When Firefox stops responding, the usual causes are a misbehaving extension, an outdated graphics driver clashing with hardware acceleration, or a corrupted user profile.
This guide walks through every fix in order, from updating Firefox and disabling extensions to clearing cache, refreshing the browser, and creating a new profile.
In this guide, I have covered:
Contents
Why Firefox freezes or stops responding
Firefox can stop responding or freeze for several reasons. A misbehaving extension or theme is one of the most common triggers, especially after Firefox updates or after the extension itself updates. Other frequent culprits are corrupted profile data, outdated graphics drivers that clash with hardware acceleration, and a large set of open tabs that exhaust memory.
Identifying the exact trigger matters less than working through the fixes below in order. Each step rules out one or more likely causes until Firefox is responsive again.
Make sure Firefox is really frozen
A slow page or a long-running script can make Firefox look frozen when it is actually just busy. Wait at least 30 seconds with the cursor over the window before deciding the browser is hung.
If the title bar still says “(Not Responding)” on Windows or the spinning beach ball is permanent on macOS, the browser is genuinely stuck. Right-clicking a link should not open a context menu either. Move on to the next steps.
Force quit and reopen Firefox
If Firefox will not respond at all, end the process and start it again. On Windows, press + + to open Task Manager, pick Firefox from the list, and click . On macOS, press + + to open Force Quit, select Firefox, then click .
Relaunch Firefox and use it normally for a few minutes to see whether the freeze returns.
Update Firefox to the latest version
Bug fixes in newer Firefox releases often resolve the exact freeze you are hitting. Mozilla ships background updates automatically, but a stalled update or a frozen system can leave you on an older build.
- Open the Firefox browser app on your computer.
- Click on the More
menu and select the Settings menu.
- Scroll down to the Firefox Updates section within the General tab, and click the button.
- Firefox will check for updates and download them. It may ask to restart to complete the installation of the update.
The browser will be updated to the latest version.
After Firefox updates and restarts, revisit the page or workflow that used to freeze and confirm it now behaves.
Start Firefox in Troubleshoot Mode
Troubleshoot Mode launches Firefox with extensions, themes, custom toolbar tweaks, and hardware acceleration temporarily disabled. If Firefox runs smoothly under Troubleshoot Mode, the cause is one of those disabled features. For the full reference, see Mozilla’s Troubleshoot Mode support article.
Click the hamburger menu in the top right of the Firefox toolbar and choose Help, then Troubleshoot Mode…. Confirm by clicking in the dialog that appears.
If Firefox is too frozen to reach the menu, hold while launching Firefox from your desktop or Start menu. On macOS, hold the key instead. Choose “Start in Troubleshoot Mode”, not “Refresh Firefox”.
If the freeze disappears under Troubleshoot Mode, return to normal mode and disable extensions one at a time to find the offender.
Turn off hardware acceleration
Hardware acceleration shifts graphics work to your GPU, but a stale driver or an unsupported card can cause Firefox to lock up on certain pages. Disabling it forces Firefox to rely on software rendering instead.
Click the hamburger menu and pick Settings. Select General in the left sidebar, then scroll to the Performance section. Uncheck Use recommended performance settings, then uncheck Use hardware acceleration when available. Restart Firefox for the change to take effect.
If the freeze was tied to hardware acceleration, try updating your graphics driver to the vendor’s latest version before turning the feature back on.
Disable extensions and themes
Extensions and themes are responsible for a large share of Firefox hangs, especially right after they auto-update. Disabling them narrows down whether an add-on is at fault.
Click the hamburger menu and choose Add-ons and themes. Switch to the Extensions panel and toggle off every extension, then test Firefox. You can also visit about:addons in the address bar to manage them in one place.
To check whether a specific site permission is involved, see how to view site information and settings in Firefox. If Firefox stops freezing with extensions off, re-enable them one at a time until the culprit returns, then keep that add-on disabled or look for an alternative.
Clear cookies, cache, and site data
A damaged cookie store or a bloated cache can lock up Firefox on certain sites. Clearing that data gives the browser a fresh slate without touching your saved passwords or bookmarks.
- Open the Firefox browser on your computer.
- Click on the More menu and select the Settings menu.
- Switch to the Privacy & Security tab and scroll to the Cookies and Site data section.
- Click on the button.
- Enable the checkbox for the 'Cookies and Site Data' and 'Cached Web Content' options.
- Hit on the option.
It will immediately delete the cache, cookies, and site data on the browser.
After Firefox restarts, visit the site that was freezing and see whether it now loads cleanly. For a deeper clean that also drops history, follow the full guide to clear browsing data in Firefox on the computer.
TIP: If Firefox already feels sluggish, also consider clearing Firefox browsing history so old entries are not slowing down autocomplete and the address bar.
Refresh Firefox to its default state
Refresh Firefox resets add-ons, themes, search engines, and many preferences without touching your bookmarks or saved passwords. It is the right step when the individual fixes above have not held.
Click the hamburger menu , then Help, then More troubleshooting information. On the troubleshooting page that opens, click at the top right and confirm. For the full walkthrough, see Mozilla’s official Refresh Firefox support article.
Refresh Firefox keeps bookmarks, browsing history, saved passwords, cookies, auto-fill data, and your personal dictionary. It only removes extensions, themes, and a handful of preferences, so it is safe to try.
Create a brand new Firefox profile
If Refresh Firefox does not resolve the freeze, the underlying profile may be corrupted. Creating a new profile isolates the issue and gives you a clean starting point without losing your existing one.
Type about:profiles in the address bar and press . Click and follow the wizard. To test it, click for the new entry, then restart Firefox.
TIP: If Firefox runs fine under the new profile but freezes under the old one, you can selectively copy bookmarks and saved logins back instead of starting over.
Check the rest of your system
When the browser itself is clean, the freeze often comes from outside Firefox. Make sure your operating system is current, your graphics drivers are updated to the vendor’s latest version, and your security software is not blocking Firefox. A quick test in another browser can confirm whether the problem follows Firefox or your machine.
Frequently Asked Questions
Why does Firefox suddenly stop responding?
A single misbehaving extension, an outdated graphics driver that conflicts with hardware acceleration, or a corrupted user profile are the three most common triggers. Background tab memory pressure is a close fourth. Working through the fixes above in order will catch the cause in nearly every case.
How do I force quit Firefox when it is completely frozen?
On Windows, open Task Manager with + + , select Firefox, and click . On macOS, press + + to open Force Quit, select Firefox, and click .
Will Refresh Firefox delete my bookmarks and passwords?
No. Refresh Firefox keeps bookmarks, browsing history, saved passwords, cookies, auto-fill data, and your personal dictionary. It only removes extensions, themes, and a handful of preferences.
What is the difference between Refresh Firefox and creating a new profile?
Refresh Firefox rebuilds settings inside your existing profile. A new profile replaces the entire user profile folder with a fresh one. Try Refresh first, then move to a new profile only if Refresh does not solve the freeze.
Should I disable hardware acceleration if Firefox keeps freezing?
Yes, it is a reasonable early step, especially on older GPUs or machines with vendor graphics drivers that lag behind. Turn it off, restart Firefox, and test. If the freeze is gone, update your graphics driver and decide whether to leave hardware acceleration off.
