How to switch from 32-bit to 64-bit Firefox

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This article only applies to Firefox on Windows.

Note: Mozilla is planning to automatically switch users from 32-bit Firefox to 64-bit Firefox in the near future, on Windows 64-bit systems with at least 2 GB RAM. For more information, see this Mozilla blog post and the Win64 Mozilla Wiki.

The 64-bit version of Firefox can provide better performance than the 32-bit version. Want to switch to the 64-bit version of Firefox? Just install the 64-bit version and uninstall the 32-bit version. Your Firefox user data (passwords, bookmarks, settings, extensions and themes, etc.) will not be removed.

  • 64-bit Firefox requires a 64-bit version of Windows 7 or higher. To find out if you are running a 64-bit version of Windows, visit this Microsoft help page.
  • Users of Microsoft Office Outlook: Before switching to 64-bit Firefox, it is recommended to temporarily change your default browser to Internet Explorer or Microsoft Edge (details below).

Follow these steps to switch to 64-bit Firefox:

  1. Go to this Mozilla Firefox download page and click on the Windows 64-bit download link.
    DownloadWin64-bit
  2. Run the setup file you've just downloaded and follow the prompts to install the 64-bit version of Firefox.
  3. Close Firefox.
  4. Now it's time to remove the 32-bit version. Open the Windows Start menu and click on SettingsControl Panel. Open the SystemPrograms panel, then select the Apps & features tabPrograms and Features panel.
  5. Scroll down the list of appsprograms until you find the Mozilla Firefox item that contains x86 in the name. Select it, and click Uninstall.
  6. Follow the prompts in the Uninstall Wizard to complete the removal of the 32-bit version.

Users of Microsoft Office Outlook:

Before switching from 32-bit Firefox to 64-bit Firefox, it is recommended that you first change your default browser to Internet Explorer or Microsoft Edge. This is important to avoid problems opening links from messages in Outlook. Afterwards, you can change your default browser back to Firefox. For more help, see:

If you skipped this step and encounter errors along the lines of "This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.", see Microsoft's article Hyperlinks are not working in Outlook or the following page for help: This operation has been cancelled due to restrictions.