Please provide more info. When I just tried that, it worked. I used the small bar at top of message list pane, clicked 'recipient' and the list immediately sorted.

Thanks for your response. I have been fondly using Thunderbird for many years and have always recommended it when addressing U3A members on the subject of email If by 'small bar' you mean the Options of File, Edit, View, Go, Message etc, I don't see Recipient there. If I select 'View' from that menu, I see a 'Sort By' Option which contains 'Recipient' but this is in faint text and does not respond. I tried unselecting 'Date' but this is not possible

I mean the little bar at top of the message list pane, the one that lists the emails in the folder. See attached screenshot.

Are you really active at 04H11?

I presume you are using Version 115.3.2. Which layout are you using?

BTW, I am in Cape Town

Are you not seeing that at top of message list? Can you send a screenshot of your main pane? Thanks.

I am using Classic view

On your screenshot, see the 'quick filter' entry on right side and an icon to its right? That is a dropdown menu and you are in 'card view' - click to change to 'table view' and then the view I described will appear.

I updated to the latest version. Now, in both card views and table views, the sort works. Also, it took me some time to notice that there are two instances of the Quick Filter button, and the Display Options is adjacent to the lower one on the extreme RHS

Many thanks for your patience, I am much happier now :-)

Happiness is good. :)