I have had a similar experience with a new monitor, Everything was too bright and pale. But since that was across ''all ''my applications, the solution was to attend to Windows' display settings. A new modern monitor may well be rather brighter than its predecessor. I do find Thunderbird's default appearance too bland and grey. I generally use a theme to brighten it up with colours and higher contrast. Whilst I am sure you can tweak colours in the Thunderbird UI, specifically, by using its userChrome.css file, it's rather a geeky way to go about it. I'd say: * consider if it's a system-wide issue and if so, look at the display settings in your OS; * if it's specific to Thunderbird, try other themes; * if you really can't find a theme, look into setting up a userChrome.css file (not for the faint-hearted).