Type about:config into the address bar and then hit the Enter key. The page loads with a warning about the impacts of changing these preferences and the effect it can have on Firefox. Click the “Accept the risk and continue” button.

In the search bar, type each of the following preferences and then set them to the value provided to the right:

devtools.onboarding.telemetry.logged = false
toolkit.telemetry.updatePing.enabled = false
browser.newtabpage.activity-stream.feeds.telemetry = false
browser.newtabpage.activity-stream.telemetry = false
browser.ping-centre.telemetry = false
toolkit.telemetry.bhrPing.enabled = false
toolkit.telemetry.enabled = false
toolkit.telemetry.firstShutdownPing.enabled = false
toolkit.telemetry.hybridContent.enabled = false
toolkit.telemetry.newProfilePing.enabled = false
toolkit.telemetry.reportingpolicy.firstRun = false
toolkit.telemetry.shutdownPingSender.enabled = false
toolkit.telemetry.unified = false
toolkit.telemetry.updatePing.enabled = false
toolkit.telemetry.reportingpolicy.firstRun = false
toolkit.telemetry.unified = false
toolkit.telemetry.archive.enabled = false
devtools.onboarding.telemetry.logged = false
toolkit.telemetry.bhrPing.enabled = false
datareporting.healthreport.uploadEnabled = false
datareporting.policy.dataSubmissionEnabled = false
datareporting.sessions.current.clean = true
datareporting.healthreport.uploadEnabled = false
datareporting.policy.dataSubmissionEnabled = false
datareporting.sessions.current.clean = true