This is from the CVS version as of Aug. 28. It's the first time I've seen this assertion failure. Prior to this, I was using the CVS version from Aug. 15. dovecot: Aug 30 16:07:52 Error: 24929 IMAP(support): UIDVALIDITY changed (1125327213 -> 1125430510) in mbox file /mailhome/new/s/b/support/mbox dovecot: Aug 30 16:08:13 Error: 24929 IMAP(support): UIDVALIDITY changed (1123616948 -> 1125414730) in mbox file /mailhome/new/s/b/support/Drafts dovecot: Aug 30 16:08:16 Error: 24929 IMAP(support): UIDVALIDITY changed (1123616948 -> 1125414730) in mbox file /mailhome/new/s/b/support/Drafts dovecot: Aug 30 16:08:36 Error: 24929 IMAP(support): UIDVALIDITY changed (1122993637 -> 1125403981) in mbox file /mailhome/new/s/b/support/Tier-2 dovecot: Aug 30 16:08:39 Error: 24929 IMAP(support): file mail-index-view.c: line 596 (mail_index_view_open): assertion failed: (index->map != NULL) dovecot: Aug 30 16:08:40 Error: child 24929 (imap) killed with signal 6 (gdb) bt full #0 0xffffe410 in ?? () No symbol table info available. #1 0xbffff548 in ?? () No symbol table info available. #2 0x00000006 in ?? () No symbol table info available. #3 0x00006161 in ?? () No symbol table info available. #4 0xb7ef1d41 in raise () from /lib/tls/libc.so.6 No symbol table info available. #5 0xb7ef3529 in abort () from /lib/tls/libc.so.6 No symbol table info available. #6 0x0809af4a in i_internal_panic_handler ( fmt=0x6 <Address 0x6 out of bounds>, args=0x6161 <Address 0x6161 out of bounds>) at failures.c:374 No locals. #7 0x0809b364 in i_panic ( format=0x80a7fac "file %s: line %d (%s): assertion failed: (%s)") at failures.c:173 No locals. #8 0x080874d6 in mail_index_view_open (index=Variable "index" is not available. ) at mail-index-view.c:615 view = Variable "view" is not available. (gdb) frame #9 0x08079ccd in index_storage_mailbox_init (ibox=0x80c78c0, index=0x80c8000, name=0x80bfe80 "Tier-2", flags=Variable "flags" is not available. ) at index-storage.c:367 367 ibox->view = mail_index_view_open(index); (gdb) p *index $3 = { dir = 0x80c80a0 "/mailhome/new/s/b/support/.imap/Tier-2", prefix = 0x80c80e8 "dovecot.index", cache = 0x80c68b0, log = 0x80c6788, mode = 384, gid = 4294967295, extension_pool = 0x80c8258, extensions = { buffer = 0x80c8288, element_size = 28}, expunge_handlers = { buffer = 0x80c81c8, element_size = 4}, sync_handlers = { buffer = 0x80c8dc8, element_size = 8}, sync_lost_handlers = { buffer = 0x80c8de8, element_size = 4}, filepath = 0x80c8c70 "/mailhome/new/s/b/support/.imap/Tier-2/dovecot.index", fd = 6, map = 0x0, hdr = 0x0, indexid = 0, lock_type = 2, shared_lock_count = 0, excl_lock_count = 0, lock_id = 14, copy_lock_path = 0x0, dotlock = 0x0, lock_method = MAIL_INDEX_LOCK_FCNTL, sync_log_file_seq = 1, sync_log_file_offset = 24, keywords_pool = 0x80c8460, keywords = {buffer = 0x80c8140, element_size = 4}, keywords_hash = 0x80c8658, keywords_ext_id = 0, last_grow_count = 0, error = 0x0, nodiskspace = 0, index_lock_timeout = 0, opened = 1, log_locked = 0, mmap_disable = 1, mmap_no_write = 0, readonly = 0, fsck = 0, sync_update = 0, mapping = 0}