Hello, The malware and phishing protection feature downloads a list of malicious sites from Google every 20–30 minutes or so. During this time, Google can set and retrieve a cookie, if your settings permit it (they do by default). * [[How does built-in Phishing and Malware Protection work?]] * [[How to stop Firefox from automatically making connections without my permission]] ---- Did you create a Block exception for ''google.com'' under Preferences → Privacy? * [[Block websites from storing site preferences or login status in Firefox]] If yes, then you shouldn't have any cookies from that domain. I note that you have several add-ons related to cookies and privacy. It's always a bad idea to install multiple add-ons that perform the same task. It's possible things don't work properly because those add-ons are conflicting. * [[Troubleshoot Firefox issues using Safe Mode]] ---- I also advise against the Masking Agent add-on. You're actually making your user agent string more unique, which makes it easier to fingerprint you. * https://panopticlick.eff.org