The recommendation in Kaspersky Internet Security Notification Center is as follows: "Secure traffic in Microsoft Windows Operating System is not monitored. There was an error while configuring Microsoft Windows Operating System. To resume monitoring, add the certificate manually." If you have Thunderbird installed in your Windows Operating System, and add the certificate manually, https://support.kaspersky.com/14620, the recommendation is still present in the Kaspersky Internet Security Notification Center. The issue is with Thunderbird, not Mozilla Firefox. Every time Thunderbird is updated to the latest version, the recommendation reappears in the Notification Center. A solution is posted at the following link: https://community.kaspersky.com/kaspersky-security-cloud-11/secure-traffic-in-window-operating-system-not-monitored-20871 Here is another solution but less time-consuming: 1 - Before installing the latest version of Thunderbird, go into Kaspersky Lab product to -> Settings -> Network settings -> Mozilla Firefox and Thunderbird, and select -> Use Mozilla certificate store. 2 - Save settings. 3 - Update Thunderbird. 4 - Select again -> Use Windows certificate store (recommended) 5 - Save settings. Currently, these steps need to be followed again before installing the latest version of Thunderbird.