On Sat 2016-07-02 20:28:41 -0400, Xu Wang wrote: > Hello all, > > I have a situation where sometimes I sync a later message. For > example, the following happens on times: > > 1a. sync message 1. > 1b. not much new > 2a. sync message 3 (which replied to message 2) > 2b. not much new > 3. sync message 2 (which replied to message 1) > 3b. not much new > > This happens because of my workflow of offlineimap. It takes a long > time to sync some folders so often I prefer to skip, but sometimes > they contain replies. on most systems, assuming standard headers, notmuch should indeed assemble these into the same thread. the relevant headers are In-Reply-To and References. Can you show those headers for this example? If they have these message-IDs: message 1: XXX message 2: YYY message 3: ZZZ then i'd expect the following headers: message 1: Message-Id: XXX <no In-Reply-To or References> message 2: Message-Id: YYY In-Reply-To: XXX References: XXX message 3: Message-Id: ZZZ In-Reply-To: YYY References: XXX, YYY If notmuch has indexed them all, they should all be part of the same thread. --dkg