How to Fix Firefox When It Keeps Crashing

Q: What does a VCRUNTIME140_1.dll error mean for Firefox?

On Windows, a missing VCRUNTIME140_1.dll file or an incomplete Visual C++ runtime installation can cause Firefox problems. Obtain the appropriate installer from Microsoft's current Visual C++ Redistributable download page, run it and restart Windows. Choose the latest supported v14 package architecture matching the affected application.

To fix Firefox when it keeps crashing, update the browser, restart your computer, then use Troubleshoot Mode to check extensions, themes and hardware acceleration. If crashes continue, test a clean profile or reinstall Firefox. Start with the desktop fixes below, or go to the phone and tablet steps for mobile Firefox.

The short version

Start with updates: Install the latest Firefox update and restart your computer.
Narrow down the cause: Troubleshoot Mode temporarily disables extensions, custom themes and hardware acceleration.
Follow the result: If Troubleshoot Mode stops the crashes, check those three causes individually.
Protect your browser data: Refresh Firefox retains bookmarks and passwords but removes extensions and resets customized settings.

Fix or check	When to use it	Main catch
Reload a page	Only page content has failed	Firefox itself must remain open
Update Firefox	First step on desktop or mobile	Use your installation's update system
Restart your computer	Before changing desktop settings	Reopen Firefox afterward
Start a new session	Restored pages trigger another crash	Recover needed pages selectively
Troubleshoot Mode	Check desktop extensions, themes and graphics	Temporarily disables these features
Disable extensions	Check an extension conflict	Enable them individually to identify the cause
Update extensions	An extension causes desktop crashes	Retest after installing updates
Restore the default theme	You use a custom desktop theme	Restart after disabling the theme
Disable hardware acceleration	Graphics processing may cause crashes	Quit and reopen Firefox
Update graphics drivers	Graphics problems persist	Choose a compatible driver
Update the operating system	Crashes persist after browser updates	Steps depend on your platform
Update security software	Desktop security software is outdated	Use each product's updater
Create a clean profile	Check existing desktop customizations	Keep the original profile
Refresh Firefox	Reset desktop settings and extensions	Removes extensions and customized settings
Reinstall over the existing copy	A Mozilla installation fails to update or open	Close Firefox before running the installer
Clean reinstall	Desktop startup crashes persist	Preserve the separate profile folder
Force stop or close the mobile app	Firefox needs to be reopened	Controls depend on your phone
Submit crash reports	Earlier fixes have not helped	Supports diagnosis rather than immediate repair
Check RAM	Desktop crashes persist in Troubleshoot Mode	Hardware faults require service

Update Firefox and restart your computer

On desktop Firefox downloaded from Mozilla, open the menu and select Help and Report > About Firefox. Older layouts call the first menu Help; on macOS, open Firefox > About Firefox instead. Wait for the download, then click Restart to update Firefox.

For the Microsoft Store edition, open Microsoft Store and select Check for Updates, then install the Firefox update. On Linux installations maintained by your distribution, use the software updater or package manager that installed Firefox, then restart the browser. If the update fails, follow the steps to update Firefox and fix update problems.

Restart your computer and reopen Firefox before changing settings. If only one page has failed and the browser remains open, reload that page first. The Windows system settings paths below use Windows 11 menus.

If restoring your previous session immediately causes another crash, click Start New Session on the recovery page. Recover needed pages selectively through the menu under History > Recently Closed Tabs or Recently Closed Windows. This lets you avoid restoring all the same content at once.

Test Firefox in Troubleshoot Mode

Open the Firefox menu and select Help and Report > Troubleshoot Mode…, then click Restart and Open. Layouts with the older menu label use Help. Repeat the activity that usually causes the crash.

When Firefox crashes before you can reach its menus, close it and hold Shift while launching it on Windows. On macOS, hold Option while launching Firefox. On Linux, launch it with this command:

firefox -safe-mode

Troubleshoot Mode temporarily disables extensions, custom themes and hardware acceleration. If Firefox stays open in this mode, check those causes individually using the next two sections. If it still crashes, continue with system updates and profile troubleshooting, because custom preferences remain active in Troubleshoot Mode.

On a managed Windows or macOS installation, your administrator may have blocked Troubleshoot Mode. Ask the administrator to remove the DisableSafeMode policy or set it to false. On Windows, Group Policy can also control the Shift startup shortcut.

Check extensions and your theme

In normal Firefox, open the menu and select Extensions and themes > Extensions. Some layouts capitalize the menu label as Extensions and Themes. Turn every enabled extension off, restart Firefox and repeat the activity that caused the crash.

If stability returns, enable extensions one at a time and test between changes. Leave the extension that brings back the crash disabled. In the extension manager, open the gear menu and select Check for Updates; when updates are offered, click Install Updates. Restart Firefox, re-enable the updated extension and test again.

If you use a custom theme, open Extensions and themes > Themes and disable the active custom theme to restore System. Restart Firefox and test before making another change. If crashes continue, check hardware acceleration next.

Check graphics acceleration and system updates

Open the Firefox menu and select Settings > Tabs and browsing > Performance. Older settings layouts use General > Performance. Uncheck Use recommended performance settings, then uncheck Use hardware acceleration when available. Quit Firefox completely and reopen it.

If that stops the crashes, graphics processing may be involved. Use your computer manufacturer's update utility or the graphics manufacturer's official support site to obtain a compatible driver; the steps to find and update your graphics driver can help identify the right hardware. Linux users should also check their distribution's updates, then retest Firefox after installation.

On Windows 11, open Start > Settings > Windows Update > Check for updates, install available updates and restart when requested. For an optional graphics driver on Windows 11, open Settings > Windows Update > Advanced options > Optional updates. When a relevant driver is offered, select it, click Download and install, then restart Windows.

On macOS, open System Settings > General > Software Update and install an available compatible update. On Linux, install your distribution's available system updates. Outdated security software can also contribute to desktop crashes, so update installed antivirus, firewall and antispyware software through each product's updater.

Test a clean profile or refresh Firefox

A clean profile helps you check whether your existing settings or customizations are involved. With the newer profile interface, click the toolbar account icon, select Profiles > + New profile, complete setup and click Done editing. Test before adding extensions or importing old customizations.

If your installation does not show that interface, enter about:profiles in the address bar and press Enter. Click Create a New Profile > Next, name the profile, keep the default folder and click Finish or Done. Restart Firefox using the new profile, keeping the original profile for data recovery.

If Firefox cannot start, close it before opening Profile Manager. On Windows, press Windows + R, enter firefox.exe -P and click OK. Choose Create Profile… and complete the profile wizard.

On macOS, open Terminal after closing Firefox. Run the following command, adjusting the executable path if Firefox is installed outside its default location:

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

Choose Create Profile… and complete the wizard. On Linux, close Firefox and open Profile Manager with the following command, then choose Create Profile… and complete the wizard:

firefox -P

Refresh Firefox removes extensions and resets customized settings while retaining bookmarks and passwords. To use it, enter about:support in the address bar, press Enter and click Refresh Firefox…. Confirm with Refresh Firefox, then click Finish after the restart. Choose your session restoration option and click Let’s go!.

The startup Troubleshoot Mode window also offers Refresh Firefox, which helps when you cannot reach the normal browser window. With the new profile management system, Mozilla specifies Firefox 150 or later for Refresh availability. If you cannot use Refresh, use the clean profile route instead.

On a managed installation, an administrator can hide the Refresh control through policy. Ask the administrator to remove DisableProfileRefresh or set it to false before using Refresh.

Reinstall Firefox when startup still fails

For a Mozilla-installed copy that fails to open or update correctly, Mozilla says reinstalling over the existing copy preserves your browser data. Download a fresh installer from the official Firefox download page by selecting Download Firefox. Close Firefox and run the installer.

A clean reinstall removes Firefox's application files; preserve the separate profile folder to keep your browser data. For a conventional Mozilla installation on Windows, close Firefox and open Control Panel > Programs > Uninstall a program. Select Mozilla Firefox > Uninstall, then complete the wizard with Next > Uninstall > Finish. Remove leftover application files from C:\Program Files\Mozilla Firefox or C:\Program Files (x86)\Mozilla Firefox, then install the fresh copy.

On macOS, a clean reinstall removes the Firefox application, so preserve the separate profile folder containing your browser data. Close Firefox, open Finder > Applications, drag Firefox to Trash, then download a fresh copy and drag it into Applications. On Linux, removal and reinstallation replace the application package; use the original package manager for both operations and preserve the separate profile folder. Removing the Snap edition on Ubuntu also removes your bookmarks, history, passwords and cookies, so back up your Firefox profile first and restore it after reinstalling.

Fix Firefox crashes on a phone or tablet

For Firefox installed through Google Play on Android, open Google Play Store, tap your profile icon and select Manage apps & devices. Under Updates available, update Firefox. To check extensions, open Firefox's three-dot menu and select Extensions, select an installed extension under Enabled and turn off Enabled; older layouts call the menu Add-ons.

On a Pixel phone, open Settings > Apps > See all apps > Firefox > Force stop, then tap OK and reopen Firefox. Other Android manufacturers use different menu labels. If crashes continue on Pixel, open Settings > System > Software update to check for an operating system update.

On iPhone or iPad, open App Store, tap your profile icon and select App Updates to install an available Firefox update. If Firefox is unresponsive on an iPhone with gesture navigation, swipe up from the bottom and pause, then swipe the Firefox preview upward and reopen it. On an iPhone with a Home button, double-press Home to reach recent apps instead, then swipe the Firefox preview upward and reopen it.

For an iOS or iPadOS update, back up your device and connect it to power and Wi-Fi first. Open Settings > General > Software Update, then tap Download and Install when an update is available and complete the displayed steps.

Use crash reports when the fixes do not help

On desktop Firefox, enter about:crashes in the address bar and press Enter. Click Submit beside recent unsent reports, then copy the submitted IDs beginning with bp- into a Mozilla community support question. Describe what triggers the crash and which troubleshooting steps you have already completed.

On Firefox for Android 136 and later, open the menu and select Settings > Privacy and security > Data collection, then turn on Automatically send crash reports. On Firefox for iOS, open the menu and select Settings; under Support, turn on Automatically Send Crash Reports. Reporting helps diagnosis and future fixes rather than immediately repairing the app.

Persistent desktop crashes, including crashes in Troubleshoot Mode, can also involve faulty RAM. Run a memory diagnostic compatible with your computer if the browser fixes have not resolved the problem. A detected hardware fault needs hardware service rather than another Firefox setting change.

Frequently Asked Questions

Can too many open tabs make Firefox unstable?

Resource exhaustion can contribute to desktop Firefox crashes. Close unnecessary tabs and other applications, and open about:processes to identify unusually expensive browser activity. In Firefox desktop 140 and later, right-click a tab and select Unload Tab to release its resources without closing it.

Should you clear cookies to fix Firefox crashes?

Clearing cookies and cached website files is a page-loading remedy, not an established fix for every whole-browser crash. Clearing cookies can also lose website sign-ins. It is more relevant when a particular page fails than when Firefox repeatedly exits.

What should you try if Firefox crashes only when printing?

Resetting Firefox's saved printer settings clears those saved settings. Open about:support, find Printing and click Clear saved print settings, then retry printing. If the failure continues, compare another browser or printer and check for a compatible printer driver update.

What does a VCRUNTIME140_1.dll error mean for Firefox?

On Windows, a missing VCRUNTIME140_1.dll file or an incomplete Visual C++ runtime installation can cause Firefox problems. Obtain the appropriate installer from Microsoft's current Visual C++ Redistributable download page, run it and restart Windows. Choose the latest supported v14 package architecture matching the affected application.

Should you follow old advice about Flash or Java plugins?

Current Firefox no longer loads the old Flash, Java or Silverlight NPAPI plugins, so updating or disabling them is not a current Firefox crash fix. Firefox 85 removed Flash support without a re-enable option. Troubleshoot current extensions and Firefox's own hardware acceleration setting instead.