Try Thunderbird which manage threads the right way since many years ( probably more than 10 )

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As a collateral benefit Thunderbird is an open source software thus you can trust it because you can check. I haved used it at a large scale company ( ~ 3000 users ). Compared with Outlook, Mail, Thunderbird was the one with the less support questions and the less malware attacks ( on a more than 10 years security supervising ). On the other hand the loser was… ; I let you guess it as an easy game 😊.

The future of Thunderbird is unsure, but I am still using it to provide me a common and efficient interface to many web mail servers which are much too slow to work with ( Gmail… ).

Try Thunderbird which manage threads the right way since many years ( probably more than 10 )

View > Sort by > Threaded

As a collateral benefit Thunderbird is an open source software thus you can trust it because you can check. I used it at a large scale company ( ~ 3000 users ). Compared with Outlook, Mail, Thunderbird was the one with the less support questions and the less malware attacks ( on a more than 10 years security supervising ). On the other hand the loser was… ; I let you guess it as an easy game 😊.

The future of Thunderbird is unsure, but I am still using it to provide me a common and efficient interface to many web mail servers which are much too slow to work with ( Gmail… ).