Do you mean that you deselect the setting and it is re-selected? When does that happen?

Yes, it has happened last 3 days. Work-around is to enter websites into "exceptions".

Hi, the steps to disable pop-up blocker permanently as follow:

1. Enter 'about:config' in the search bar. 2. Click on the 'Accept the Risk and Continue' button. 3. Search for 'access' and look for 'accessibility.blockautorefresh' 4. Click on the toggle icon of the search results. (from true to false)

Hope this helps. Best Regards!

That preference has nothing to do with pop-ups. I suggest trying a new profile. You can create one with Firefox open or closed.

https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_what-information-is-stored-in-my-profile