I dont know what you did to it but the latest version 57 of Firefox is terrible. It's performance mimics a virus infected computer. It freezes constantly. I have now reerted to verion 56 which works fine for me. I am now on the setting to not upload any updates. If you want people to update make sure the update is not a festering turd before you force [people into it. And thank you for the directions on how to revert to an older version, ''Edited by a moderator due to language. See the [https://support.mozilla.org/en-US/kb/forum-rules-and-guidelines Forum Rules & Guidelines] .''