More information about Private Browsing mode. *https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history *https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing If you want to disable PB mode, you need to use a policy.json file. *https://mozilla.github.io/policy-templates/ *https://github.com/mozilla/policy-templates/tree/master/mac *https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson