I just tried the latest version from CVS and got this error: dovecot: Mar 29 18:11:33 Error: 27526 IMAP(todd.bluegenesis.com): Corrupted index cache file /mailhome/new/t/b/todd.bluegenesis.com/.imap/INBOX/dovecot.index.cache: Duplicated field in header: hdr.RESENT-TO dovecot: Mar 29 18:11:33 Error: 27526 IMAP(todd.bluegenesis.com): file index-mail-headers.c: line 68 (index_mail_parse_header_finish): assertion failed: (match[match_idx] != mail->header_match_value + 1) dovecot: Mar 29 18:11:34 Error: child 27526 (imap) killed with signal 6 I deleted the index files, didn't help. I checked my mailbox and there aren't any mails with a duplicate "Resent-To" header. With older versions of dovecot, I still get this error, but it does not abort. (Using mbox, if it matters) Here's a backtrace: Core was generated by `imap'. Program terminated with signal 6, Aborted. #0 0xffffe410 in ?? () (gdb) bt #0 0xffffe410 in ?? () #1 0xbffff528 in ?? () #2 0x00000006 in ?? () #3 0x00006b86 in ?? () #4 0xb7ef1d41 in raise () from /lib/tls/libc.so.6 #5 0xb7ef3529 in abort () from /lib/tls/libc.so.6 #6 0x0809744a in i_internal_panic_handler ( fmt=0x6 <Address 0x6 out of bounds>, args=0x6b86 <Address 0x6b86 out of bounds>) at failures.c:374 #7 0x08097864 in i_panic ( format=0x80a3bcc "file %s: line %d (%s): assertion failed: (%s)") at failures.c:173 #8 0x080748cf in index_mail_parse_header (part=0x0, hdr=0x0, mail=0x80c2f20) at index-mail-headers.c:210 #9 0x08090963 in _read (stream=0x80c3be8) at istream-header-filter.c:170 #10 0x0809a293 in i_stream_read (stream=0x80c3c0c) at istream.c:51 #11 0x0809a4d1 in i_stream_read_data (stream=0x80c3c0c, data=0xbffff7c4, size=0xbffff7c8, threshold=58) at istream.c:229 #12 0x08092f5f in message_parse_header_next (ctx=0x80c1920, hdr_r=0xbffff7f8) at message-parser.c:735 #13 0x0809363e in message_parse_header (part=0x0, input=0x80c3c0c, hdr_size=0x0, callback=0x80757c0 <search_header>, context=0xbffff880) at message-parser.c:655 ---Type <return> to continue, or q <return> to quit--- #14 0x08075640 in index_storage_search_next (_ctx=0x80c5568, mail=0x80c2f20) at index-search.c:502 #15 0x0808b705 in mailbox_search_next (ctx=0x6, mail=0x80c2f20) at mail-storage.c:405 #16 0x08057bee in cmd_search (cmd=0x80ba980) at cmd-search.c:33 #17 0x080594f5 in _client_input (context=0x80ba940) at client.c:334 #18 0x0809c5da in io_loop_handler_run (ioloop=0x80b95b0) at ioloop-poll.c:184 #19 0x0809bcf9 in io_loop_run (ioloop=0x80b95b0) at ioloop.c:218 #20 0x080603a7 in main (argc=1, argv=0xbffffa74, envp=0xbffffa7c) at main.c:229 (gdb)