I've been using Thunderbird as my e-mail client for a while now - it's great. It recently (last few days (today = 5/10/23)) did an automatic upgrade. With the new version the basic font size was smaller. So the lists of all e-mails in inbox, sent box etc etc were in a smaller font than before. I find them a bit small for reading. I googled how to change this and found a page that said to to Settings... search for EditorConfig and then change the parameter layout.css.devPixelsPerPx This was set at -1.0 (note negative sign) I tried changing it to 16. A MISTAKE! Now everything Thunderbird related is huge! On my screen I can only see the menu items File Edit View - these now fill the whole width of the screen. Thunderbird has become unusable. I attach a screen shot of my whole screen.... I can't seem to move the window contents around so I can't get anywhere near the Settings menu item. Because I can't see anything of any value, I can''t get back to Settings to change the configuration back. Two questions: a) is there a way to change this setting back to -1.0 without using Thunderbird (eg my manually editing a text file or the windows registry)? b) is this the right way to increase the basic font size used by the Thunderbird user GUI? Regards, Roger