Hello

Take a look at https://connect.mozilla.org/t5/discussions/layout-css-devpixelsperpx/td-p/42594

Or Check Thunderbird are stopped Then Go to your profile https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data and find your prefs.js file and open with your notepad and delete line user_pref("layout.css.devPixelsPerPx", "125"); And save prefs.js and restart Thunderbird.

I have closed Thunderbird. I read the post. My system language is German. i don`t see the Charms to select Search, unless I am supposed to search on top right, like the screenshot shows. When I do so, there is no result, which might have to do with the language. I cannot open Thunderbird.

When using the alternative (Alternatively, you can find your profile by pressing the Windows Key key and then start typing: %APPDATA%\Thunderbird\Profiles\) there is also no result due to the search term being in English, I suppose

Thank you for your reply, but I need more information please or the correct translation to German for %APPDATA%\Thunderbird\Profiles\

I got as far as to the Roaming folder after making hidden folders visible, however there is no Thunderbird folder in it. See screenshot.

- on windows desktop, click the windows key and the letter 'r' to open a small window - in that, enter %appdata% and press enter key - that should take you to the appdata\roaming folder - click the thunderbird folder and then the profiles folder - this is where profile folder is. if there are more than one, look for the one with prefs.js and latest date - open prefs.js with notepad. locate the entry and replace content with -1.0 and save - restart thunderbird