> malloc: *** error for object 0x7fff5fba8a10: pointer
> being freed was not allocated *** set a breakpoint
> in malloc_error_break to debug
> any ideas? fetched about 18.000 files previously
> before it crashed... I am on osx using 3.45-3-nossl

Humm, nope :(

Without reproducible case, it is very hard to guess where might be the problem
- do you have any stack trace along with this error by chance ?