Emailed about this with 1.1rc3 and didn't get a reply. Tried upgrading to 1.1rc4 and got the same crashing:

Centos 5 (in openvz container) 2.6.18-53.1.4.el5.028stab053.4 #1 SMP Fri Jan 18 12:29:44 MSK 2008 x86_64 x86_64 x86_64 GNU/Linux

/usr/local/dovecot/sbin/dovecot -n # 1.1.rc4: /usr/local/dovecot/etc/dovecot.conf log_path: /var/log/dovecot.log protocols: imap imaps pop3 pop3s listen(default): *:10143 listen(imap): *:10143 listen(pop3): *:10110 ssl_listen(default): *:10943 ssl_listen(imap): *:10943 ssl_listen(pop3): *:10993 ssl_cert_file: /usr/local/dovecot/etc/ssl/certs/dovecot.pem ssl_key_file: /usr/local/dovecot/etc/ssl/private/dovecot.pem ssl_cipher_list: ALL:!LOW:!SSLv2 disable_plaintext_auth: no login_dir: /usr/local/dovecot/var/run/dovecot/login login_executable(default): /usr/local/dovecot/libexec/dovecot/imap-login login_executable(imap): /usr/local/dovecot/libexec/dovecot/imap-login login_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3-login login_user: dovecot-auth first_valid_uid: 2000 last_valid_uid: 2000 first_valid_gid: 2000 last_valid_gid: 2000 mail_uid: 2000 mail_gid: 2000 mail_drop_priv_before_exec: yes mail_executable(default): /usr/local/dovecot/libexec/dovecot/imap mail_executable(imap): /usr/local/dovecot/libexec/dovecot/imap mail_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3 mail_plugins(default): fts fts_squat quota imap_quota mail_plugins(imap): fts fts_squat quota imap_quota mail_plugins(pop3): expire quota mail_plugin_dir(default): /usr/local/dovecot/lib/dovecot/imap mail_plugin_dir(imap): /usr/local/dovecot/lib/dovecot/imap mail_plugin_dir(pop3): /usr/local/dovecot/lib/dovecot/pop3 auth default: default_realm: flerd.com verbose: yes debug: yes passdb: driver: ldap args: /usr/local/dovecot/etc/dovecot-ldap.conf userdb: driver: prefetch userdb: driver: ldap args: /usr/local/dovecot/etc/dovecot-ldap.conf socket: type: listen client: path: /usr/local/dovecot/var/run/dovecot/auth-client mode: 438 master: path: /usr/local/dovecot//var/run/dovecot/auth-master mode: 438 user: dovecot-auth plugin: fts: squat quota: dict:user::proxy::quotadict quota_rule: *:storage=1G quota_rule2: Trash:storage=100M expire: Trash 7 Trash/* 7 Spam 3 expire_altmove: * 30 expire_dict: proxy::expire dict: quotadict: mysql:/usr/local/dovecot/etc/dovecot-dict-quota.conf expire: db:/usr/local/dovecot/var/lib/dovecot/expire.db

Core was generated by `imap'. Program terminated with signal 11, Segmentation fault. #0 0x00000000004640f9 in mail_index_get_header_ext (view=0x0, ext_id=2, data_r=0x7fffdbbcff90, data_size_r=0x7fffdbbcff88) at mail-index-view.c:550 550 view->v.get_header_ext(view, NULL, ext_id, data_r, data_size_r); (gdb) bt full #0 0x00000000004640f9 in mail_index_get_header_ext (view=0x0, ext_id=2, data_r=0x7fffdbbcff90, data_size_r=0x7fffdbbcff88) at mail-index-view.c:550 No locals. #1 0x000000000044631c in dbox_sync_want_flush_dirty (mbox=0xdd47598, close_flush_dirty_flags=true) at dbox-sync.c:262 hdr = <value optimized out> data = <value optimized out> data_size = <value optimized out> #2 0x00000000004463d1 in dbox_sync_begin (mbox=0x0, ctx_r=0x7fffdbbd00c8, close_flush_dirty_flags=144, force=144) at dbox-sync.c:297 storage = (struct mail_storage *) 0xdd3dc98 ctx = <value optimized out> sync_flags = <value optimized out> ret = <value optimized out> rebuild = <value optimized out> #3 0x0000000000446b98 in dbox_sync (mbox=0x0, close_flush_dirty_flags=144) at dbox-sync.c:396 sync_ctx = (struct dbox_sync_context *) 0xdd47598 #4 0x000000000043f3f4 in dbox_storage_mailbox_close (box=0x0) at dbox-storage.c:311 mbox = <value optimized out> ret = <value optimized out> #5 0x00002aaaab62df50 in fts_mailbox_close (box=0xdd47598) at fts-storage.c:65 fbox = (struct fts_mailbox *) 0xdd48fb0 ret = <value optimized out> #6 0x00002aaaab42a5ed in cmd_getquotaroot (cmd=0xdd3e758) at imap-quota-plugin.c:98 storage = <value optimized out> box = (struct mailbox *) 0x0 iter = (struct quota_root_iter *) 0x0 root = <value optimized out> orig_mailbox = 0xdd42938 "INBOX" mailbox = 0x49ab6a "INBOX" str = (string_t *) 0xdd311c0 #7 0x000000000041abfc in client_command_input (cmd=0xdd3e758) at client.c:553 client = (struct client *) 0xdd3e370 command = <value optimized out> __PRETTY_FUNCTION__ = "client_command_input" #8 0x000000000041acb2 in client_command_input (cmd=0xdd3e758) at client.c:602 client = (struct client *) 0xdd3e370 command = (struct command *) 0x7fffdbbcff90 __PRETTY_FUNCTION__ = "client_command_input" #9 0x000000000041b46f in client_handle_input (client=0xdd3e370) at client.c:643 _data_stack_cur_id = 3 ret = <value optimized out> remove_io = <value optimized out> handled_commands = false #10 0x000000000041b693 in client_input (client=0xdd3e370) at client.c:698 cmd = <value optimized out> output = (struct ostream *) 0xdd3e608 bytes = 27 __PRETTY_FUNCTION__ = "client_input" #11 0x0000000000486de8 in io_loop_handler_run (ioloop=<value optimized out>) at ioloop-epoll.c:201 ctx = <value optimized out> event = (const struct epoll_event *) 0xdd39dc0 list = (struct io_list *) 0xdd3a780 io = (struct io_file *) 0xdd3e6a0 tv = {tv_sec = 1799, tv_usec = 999607} events_count = <value optimized out> t_id = 2 msecs = <value optimized out> ret = 1 i = 0 call = <value optimized out> #12 0x00000000004860cd in io_loop_run (ioloop=0xdd39b60) at ioloop.c:301 No locals. #13 0x0000000000422b01 in main (argc=<value optimized out>, argv=0x0, envp=0x7fffdbbd03c8) at main.c:293 No locals.