I cannot start another profile from "about:profiles" - always only opens the same profile that is open already. I have now read a bit about this on Mozilla. It seems they do not like profiles as a principle. So, it seems I do have to change to Chrome. My use of profiles: Yes, I do a bit of private web development but I that is not the main reason I use profiles. I separate my work areas by browser profiles each with multiple tabs open. Having all those tabs in one browser window would make it very chaotic. One window has social media, another has private surfing websites, another company info sites... and so on