Javier Garcia <javiertury@gmail.com> writes:

> I can't build a healthy database for notmuch. My mail directory has
> quite a few mails, around 20,000.
>
> $ rm -rf ~/.mail/.notmuch
> $ notmuch new
> $ xapian-check ~/.mail/.notmuch/xapian/
>> docdata:
>> blocksize=8K items=63 firstunused=1 revision=2 levels=0 root=0
>> B-tree checked okay
>> docdata table structure checked OK
>>
>> termlist:
>> blocksize=8K items=43520 firstunused=8291 revision=2 levels=2 root=748
>> xapian-check: DatabaseError: 1 unused block(s) missing from the free
> list, first is 0
>

There was recently a similar report that turned out to be related to a
reference loop in the mail.  Do you actually have any symptoms of
database corruption other than the message about the free list? if not,
it might be worth trying the attached patch, which attempts to break
reference loops.