Resist Fingerprinting in Waterfox

Resist Fingerprinting is an advanced privacy feature that limits or standardizes information websites can use to distinguish your device from others. It is more disruptive than the fingerprinting protections included with Enhanced Tracking Protection and can cause websites to behave incorrectly.

The main preferences are privacy.resistFingerprinting, which applies to regular browsing, and privacy.resistFingerprinting.pbmode, which applies in Private Browsing. An extension or managed preference can enable them even if you did not change them directly.

Check and disable Resist Fingerprinting

1. Enter about:config in the address bar and press Enter.
2. If a warning page appears, select Accept the Risk and Continue.
3. Search for privacy.resistFingerprinting.
4. Check whether privacy.resistFingerprinting or privacy.resistFingerprinting.pbmode is set to true.
5. Use the toggle button to set each unwanted preference to false, then restart Waterfox.

If a preference returns to true, an extension or device policy may control it. Disable extensions one at a time and restart Waterfox after each change. On a managed device, ask the administrator whether a policy sets the preference.

How Resist Fingerprinting can affect websites

These effects are intentional tradeoffs that reduce identifying information. Depending on the platform and page, you may notice:

• Times displayed in UTC or another unexpected time zone
• Pages choosing an unexpected language or platform-specific download
• Noise or artifacts in images produced from canvas content
• Slower or less smooth animations and games
• Blurry maps, icons or images
• Gamepads, sensors, styluses or touch input not working as expected
• Light, dark, motion, transparency or contrast preferences not being detected
• New windows opening at standardized dimensions
• Fixed colors appearing instead of system colors

If these effects disappear after both preferences are set to false, Resist Fingerprinting was likely the cause.

What Resist Fingerprinting changes

The exact protections can change between Waterfox releases and vary by platform. They generally include:

• Protecting canvas image extraction with randomized or restricted output unless permission is granted
• Standardizing time zone, locale, platform and user-agent details
• Limiting the fonts a site can enumerate
• Reducing timer precision and standardizing some media capability values
• Limiting details about cameras, microphones, sensors, gamepads and speech voices
• Standardizing screen, window, pointer, touch and hardware values
• Returning fixed values for selected CSS preference queries

These changes make Waterfox users with the feature enabled look more similar to one another, but they can also remove information a site needs for normal behavior.

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