In what way is Twitter broken? Do you get a specific error message we might be able to help with? ---- One thing that happens after a Refresh is that Firefox starts in single-process mode. It then assesses your system and usually sets a flag to start up in multi-process mode in future sessions. So perhaps there's an issue there... One of the main technical changes in Firefox 54 was to enable more individual content processes. In Firefox 48-53, the Firefox multiprocess feature would create one process for the UI and one process for content. Now Firefox will aim for four content processes. Perhaps this is an unexpected side effect of this change?? You could try rolling back the number of content processes to 1. If this doesn't work, you may need to revert to single-process mode. Here's how you can try this: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful. (2) In the search box above the list, type or paste '''ipc''' and pause while the list is filtered (3) If the '''dom.ipc.processCount''' preference is bolded and "user set" to 4, double-click it and edit the value to 1, then click OK Presumably that will not take effect until the next startup, at which time you should check it to make sure it hasn't reverted back. Any difference? Alternately, you can disable multiprocess mode using a different preference: <p>(4) In the search box above the list, type or paste <strong>autos</strong> and pause while the list is filtered</p> <p>(5) Double-click the <strong>browser.tabs.remote.autostart.2</strong> preference to switch the value from true to false</p> <p><em>Note: the exact name of the preference may vary, but it will start with browser.tabs.remote.autostart</em></p> <p>At your next Firefox startup, it should run in the traditional way. Any difference?</p>