On 24 Jul 2015, at 12:58, Sergey Schwartz <sergey.schwartz at bgoperator.com> wrote: > > I've got a bit more details > > Jul 24 10:21:50 mx10 dovecot: imap(oleg.vasilyev at bgoperator.com): *Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset): assertion failed: (offset < 0x40000000)* I think you have a huge >4 GB dovecot.index.cache file there?