Are you using a bookmark to load those pages? If so, edit the "Location" line in Properties for those bookmarks to get rid of the '''m.''' Or make sure that you aren't using bookmarks that were saved on a "mobile" device if you are using Sync to synchronize your bookmarks with a laptop / desktop computer and a "mobile" device. Beyond that, take a look at Help > Troubleshooting Information and verify that the User Agent line doesn't have User Agent information for a mobile device; i.e., mention Android or iOS. If you don't understand what I am referring to, just copy the User Agent code and paste into the reply box here. Like this: '''Mozilla/5.0 (Windows NT 6.1; rv:44.0) Gecko/20100101 Firefox/44.0''' Firefox 44.0 on a Windows 7 desktop PC. "Something" is telling those websites to send the '''m'''obile version of the webpage to your PC; either bookmark has the '''m.''' in the URL or Firefox is telling the website that you are using a "mobile" browser.