Hi I read these articles and they doesnt help to resolve the problem https://support.mozilla.org/en-US/questions/1349609 https://support.mozilla.org/bm/questions/1206172 https://www.reddit.com/r/firefox/comments/ip88y7/firefox_is_preventing_windows_10_from/?rdt=53488 Problem: I have Win10. Firefox 107. I have noticed that if I have opened only regular/textual web pages in my tabs like news/articles then PC goes to sleep after specified time of inactivity. But if I open in the one tab some media content like videoclip/animation/movies and put media content on pause then PC doesnt go to sleep after specified time. PC goes to sleep only by manual command (Start>Sleep). Even If I close the tab with media content PC doesnt go to sleep after specified time. I should or totally close the browser with all opened tabs or manually select Start>Sleep. Could you help to resolve this issue ? On the screenshots are shown that some of firefox processes couldn't stop making some activity, every second they make some web request or disk operation. May be this is reason why PC cant go to sleep. But again, this is happen only or some media content is put on pause or some tab with media content has been closed.