I too have had mail quit unexpectedly for quite a while. Any solutions at this time?Mail_2020-09-19-002013_Garys-iMac.crash (124.4 KB) Mail_2020-09-17-002020_Garys-iMac.crash (120.4 KB) Mac High Sierra 10.13.6 (17G14019) on a mid 2010 iMac
I’ve seen these crashes before, and I think they’re caused by a bug in Mail that Apple fixed in macOS 10.14. I don’t think they’re related to SpamSieve, but if you wanted to test that you could temporarily uncheck the SpamSieve rule in Mail’s preferences.
Unfortunately this Mac is too old to download 10.14 and my other Mac running 10.15.6 does not have the problem. Any other thoughts?
It may help to remove the mail account in Mail’s preferences and then add it again. (It seems to be an IMAP account, so Mail would just redownload the messages from the server, although any rules might need be adjusted.)