Updating Lightning to version 4.7 didn't change the situation.

Since Lightning is bundled with Thunderbird there is no need to manually update Lightning. It should happen automatically.

Are you saying you did manually install Lightning 4.7? If so, why?

Because it didn't work anymore after upgrade of TB. See title.

Anyway, I've meanwhile downgraded TB once and updated it again, which has solved the problem.

I found a solution detailed under Debian Bugs - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=833532#50

Start Thunderbird in safe mode.

Enter preferences - advanced - config editor change the value of javascript.options.baselinejit to false.

Restart Thunderbird normally.

HTH!

toad_of_toadhall said

Start Thunderbird in safe mode.

Don't know what safe mode is and how to start TB that way. However, had this problem again after upgrade to 45.5.0 and simply changing the value of javascript.options.baselinejit to false, as you suggested and restarting TB solved it for me this time.

Thanks a lot.

had this problem again after upgrade to 45.5.0 and simply changing the value of javascript.options.baselinejit to false, ... and restarting TB solved it for me this time.

I'd just hope you'll mention that little detail the next time you have a problem.

Don't know what safe mode is and how to start TB that way.

https://support.mozilla.org/kb/safe-mode-thunderbird

christ1 said

I'd just hope you'll mention that little detail the next time you have a problem.

Which little detail are you referring to? That I didn't need safe mode or that I've changed javascript.options.baselinejit to false?