--- ./src/master/master-settings.c +++ ./src/master/master-settings.c 2019-05-26 23:25:08.000000000 -0400 @@ -210,9 +210,9 @@ .protocols = "imap pop3 lmtp", .listen = "*, ::", .ssl = "yes:no:required", - .default_internal_user = "dovecot", - .default_internal_group = "dovecot", - .default_login_user = "dovenull", + .default_internal_user = "_dovecot", + .default_internal_group = "_dovenull", + .default_login_user = "_dovenull", .default_process_limit = 100, .default_client_limit = 1000, .default_idle_kill = 60, @@ -223,7 +223,10 @@ .first_valid_uid = 500, .last_valid_uid = 0, .first_valid_gid = 1, - .last_valid_gid = 0, + /* macOS: `last_valid_gid = 100` to avoid the error */ + /* imap: Fatal: setgroups(501) failed: Too many extra groups */ + /* https://www.systemcodegeeks.com/mac-os/macos-dovecot-setgroups-failed/ */ + .last_valid_gid = 100, #ifndef CONFIG_BINARY .services = ARRAY_INIT