I have not made the switch to ver. 60 yet but I see this in the release notes.

An option under "Tools > Options, Advanced, General" now allows to select whether date/time display will follow the application locale (adjusted by operating system's format settings for that locale) or the locale selected in the operating system's regional settings. In other words, an US English Thunderbird can use, for example, German formats.

Is there an option there that helps you?

thanks a lot it solved the issue. I missed that item when I went through the options.

Best regards

Andi

I've the same, or very similar issue. I'd like to just tell Thunderbird to use 24h clock format for dates.

My system is configured to use English (us) with US keyboard but with 24 hour clock. I'm guessing that Thunderbird just takes the "US" part and assumes everything else.

Is it possible to manually override settings that Thunderbird guesses from the system ?

Hi BatManuel, Airmail's post was marked as the solution by the person who asked the original question (Andi). Your issue may have similar symptoms, but it is likely a different cause/solution. You should use https://support.mozilla.org/en-US/questions/new where volunteers can get more details about your setup.

Because this thread is solved and more people might start using it for their own questions, I'm going to lock it.