Hello, we have a set of 250 pcs under linux and we just have updated some of them to Firefox 59. Since then it seems Firefox is just ignoring the /etc/firefox/syspref.js file. We have been using that file for a while now to set for example default home page, proxy etc.... Until Firefox 58 it's used to work just fine. Now the file is ignored what ever we put into it. We tried to delete ~/.mozilla folder for users to rebuild it as new, doesn't help. One example file we have used so far and was working fine till Firefox 59 #cat firefox/syspref.js // set the proxy for all users lockPref("network.proxy.http","10.166.1.254"); lockPref("network.proxy.http_port",3128); lockPref("network.proxy.ssl","10.166.1.254"); lockPref("network.proxy.ssl_port",3128); lockPref("network.proxy.ftp","10.166.1.254"); lockPref("network.proxy.ftp_port",3128); lockPref("network.proxy.type",1); lockPref("browser.startup.homepage","https://www.google.fr"); lockPref("intl.accept_languages","fr-fr,fr"); pref("media.libavcodec.allow-obsolete", true); pref("plugins.http_https_only", false); Thanks for advice