Accessibility features are not yet fully supported in multiprocess Firefox. If third-party software (screen readers, Windows touchscreen software or anti-spyware) requests access to Firefox's accessibility features, Firefox limits this access to web content to prevent stability issues. Restarting Firefox will change it back to single process mode and re-enable accessibility features automatically.

How to re-enable Firefox's accessibility features

1. To fully enable accessibility features after having received a notification, restart Firefox. It will restart in single process mode.
2. To force enable electrolysis for testing purposes, go to the Configuration Editor (about:config page) and set the browser.tabs.remote.force-enable preference to true.
   Warning: Changing advanced preferences can affect Firefox's stability and security. This is recommended for advanced users only.
3. Avoid running third-party software that request accessibility features within Firefox.