Hi tomC9000, I'm not sure there's a relationship between those two things. The "Keep until" setting for cookies determines whether Firefox honors the site's requested cookie expiration date -- which could be years from now -- or sets every cookies to expire at the end of the current session (when you exit Firefox). Is there an article which says this might affect video autoplay? Anyway, that setting is grayed (and should show "Keep until: I close Firefox") if you are using automatic private browsing mode. In that mode, all cookies are dumped when you close the last private window and you can't retain website cookies longer than that. You can check whether you are using automatic private browsing. One of these will be set in the History section of the page: * Firefox will: Never remember history * Firefox will: Use custom settings for history ''plus'' ** Always use private browsing mode is turned on ---- To the larger issue of auto-play: if the main issue is with ads, there are add-ons directed toward suppressing unwanted ads. If the main issue is with content videos, it's trickier.