What is the Accessibility Service Indicator?

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This article describes a feature that will be available in Firefox version 57 and above.

What is the Accessibility Service Indicator?

An accessibility 57 icon displayed in the Firefox tab bar which communicates to users that Firefox Accessibility Service is enabled and in use.

What is Firefox Accessibility Service?

Firefox Accessibility Service is a technology built into Firefox that provides 3rd party applications running on the same device the ability to inspect, monitor, visualize, and alter web page content hosted within Firefox.

Assistive Technologies

Applications that provide access to web content hosted in Firefox for users with physical impairments often enable Firefox Accessibility Service. This is the intended use of Firefox Accessibility Service.

Anti-Virus and Anti-Malware Browser Plugins

Often described as "browser protections" promoting security improvements, these features rarely add valuable security to Firefox and other browsers. Most are poorly designed and poorly tested, and can inadvertently disable more effective security measures built into Firefox. These features also often cause problems during upgrades to Firefox, triggering nasty startup crashes and other abnormalities.

Mozilla does not support or sanction this use of Accessibility Service and actively works with anti-virus vendors to migrate their Accessibility Service extensions to other Firefox extension mechanisms designed for this use.

Mozilla recommends disabling these anti-virus features if they enable Firefox Accessibility Service.

Enterprise or Educational Monitoring and Access

Corporate sign-on assistive technologies, copyright protection, employee and student monitoring, and remote access through remote desktop technologies often turn Firefox Accessibility Service on.

Niche Shareware or Freeware applications

Firefox Accessibility service is occasionally consumed by niche software applications that interact with your web browser to accomplish unique tasks or duties. Examples include: automatic web page form filling, time use tracking, and media managers.

Mozilla does not support or sanction this use of Accessibility Service and suggests these application vendors migrate their software to more appropriate browser extension mechanisms.

Mozilla recommends disabling or uninstalling these applications if they enable Firefox Accessibility Service.

Malware and Adware

Firefox Accessibility Service can be abused by malware, if present, to monitor user behavior or access user information on the web.

If you suspect your device is infected with malware, consider purchasing and running a competent anti-malware software product to address the issue.


What is the impact of having Firefox Accessibility Service enabled?

  • Firefox Accessibility Service may negatively impact Firefox browsing performance
  • Third party applications may be monitoring your web surfing activity
  • Firefox stability may be adversely affected

My Accessibility Service Indicator is visible, what should I do?

A 3rd party application is accessing your browser through Firefox Accessibility Service. Investigate what software might be involved to determine if you feel this access is acceptable. If you do not, consider uninstalling or disabling the application accessing Firefox Accessibility Service. If this is not possible, consider disabling Firefox Accessibility Service within Firefox.

  1. Enter about:support in the address bar. The Troubleshooting Information page will open.
  2. Find the "Accessibility" section and look at the value in the "Accessibility Instantiator" entry.
  • blank - No client information was retrieved
  • An application path that points to a program that accessed Firefox Accessibility Service.
Example path information C:\Windows\System32\Magnify.exe
  • An encoded value, for example: 'NVDA' indicating Firefox recognized the application. Listed below are common values and a description of the client detected.
Value Description
'NVDA' NVDA screen reader
'JAWS' A compatible version of JAWS screen reader
'OLDJAWS' An incompatible version of JAWS screen reader detected

Should I disable Firefox Accessibility Service?

Assistive Technologies

Do not disable Firefox Accessibility Service if you or someone who shares your device accesses the web through Firefox using any type of physical impairment assistive software.

Anti-Virus and Anti-Malware Browser Plugins

If you determine an anti-virus software extension is enabling Firefox Accessibility Service Mozilla recommends you disable this 3rd party software feature. If a disable configuration option is not available Mozilla recommends disabling Firefox Accessibility Service from with Firefox.

Enterprise or Educational Monitoring and Access

Users in enterprise or educational networks should contact their administrator about disabling Firefox Accessibility Service.

Niche Shareware or Freeware applications

If you determine a 3rd party desktop application is enabling Firefox Accessibility Service and you are experiencing slowness or other performance related problems in Firefox, Mozilla recommends you disable or uninstall the 3rd party application. If you are unable to disable or uninstall, Mozilla recommends disabling Firefox Accessibility Service from with Firefox as a work around.

How do I disable Firefox Accessibility Service?

  1. Click the menu button Fx57Menu and choose OptionsPreferences.
  2. Select the Privacy & Security panel.
  3. Go to the Permissions section.
  4. Check the Prevent accessibility services from accessing your browser checkbox.
  5. Restart Firefox.

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