I need to disable E10s. It causes Firefox 68,0 (32bit) to display a Blank Page when Firefox is closed and I launch a Web Page from my Email Client. I have to have Firefox open first now before clicking on a Website url from the Email Client. This was the same problem I had two or more years ago when E10s was first implemented. I disabled it back then in about:config but Mozilla have disabled that option in Firefox 68. It's stated you can disable E10s using Environment Variable MOZ_FORCE_DISABLE_E10S - 1 but I'm not sure where to use that. I put it in my Windows 10 Environment Variables (System Properties/Environment Variables) but it did not work. I am using Windows 10 32-bit (Both Pro and Home) and the problem exists on all computers since upgrading to Firefox 68.0. I need to disable E10s again.