Update on my experiences with #DavMail and #mbsync: after a lot of experimentation, it turned out that the problem of unsynced messages occurred with messages above a certain size. Apparently DavMail behaves in a way that differs from other #IMAP servers and that mbsync doesn’t handle well.
I’ve massively increased the size of buf in src/socket.h (from 100000 to 5000000), and this seems to have solved the problem. The real problem is probably in the protocol handling, but this is at least a workaround that allows me to continue reading mail with #mu4e in #Emacs.
@sqrtminusone That’s interesting, thanks for sharing! I guess I’ll try #OfflineIMAP at some point then. With #DavMail in the loop, the performance difference between #mbsync and OfflineIMAP should be negligible…
@true_mxp I just switched to #OfflineIMAP for use with #DavMail.
But my problem was that my Exchange instance somehow assigned duplicate UIDs to different emails in different folders, so #mbsync just couldn't download a large part of my mail. And OffineIMAP had some way to handle that more gracefully.