Got this using dovecot-1.1 (hg version of 2 days ago). I mean with http://hg.dovecot.org/dovecot-1.1/rev/c4342385d696 included. Regards, Diego.

Panic: IMAP(username): Trying to close mailbox INBOX with open transactions (gdb) bt #0 0x007c3402 in __kernel_vsyscall () #1 0x00138ba0 in raise () from /lib/libc.so.6 #2 0x0013a4b1 in abort () from /lib/libc.so.6 #3 0x080d49f0 in default_fatal_finish (type=LOG_TYPE_PANIC, status=0) at failures.c:152 #4 0x080d523a in i_internal_fatal_handler (type=LOG_TYPE_PANIC, status=0, fmt=0x80f6c34 "Trying to close mailbox %s with open transactions", args=0xbf8648c4 "8^\\\b�H\206���\005\b\210�[\bN�\016\b�H\206�NI\016\b��[\bh�[\b\030I\206��\023\006\b��[\b��[\b\bI\206�2�\016\b��[\b�$") at failures.c:418 #5 0x080d4b2a in i_panic (format=0x80f6c34 "Trying to close mailbox %s with open transactions") at failures.c:193 #6 0x080a5126 in mailbox_close (_box=0x6) at mail-storage.c:471 #7 0x0805edb8 in cmd_logout (cmd=0x85bd7d8) at cmd-logout.c:18 #8 0x080613dc in client_command_cancel (_cmd=0x85bd3c4) at client.c:75 #9 0x08061662 in client_destroy (client=0x85bd368, reason=0x80eee5b "Connection closed") at client.c:134 #10 0x0806285e in client_input (client=0x85bd368) at client.c:697 #11 0x080df05a in io_loop_handler_run (ioloop=0x85bb9b0) at ioloop-epoll.c:201 #12 0x080de2a2 in io_loop_run (ioloop=0x85bb9b0) at ioloop.c:308 #13 0x0806dd14 in main (argc=1, argv=0xbf864ab4, envp=0xbf864abc) at main.c:293