Thanks to amdragon's hint on how to get a stacktrace, here it is. I startet gdb --args python, imported my stuff and ran it directly. I can't really interpret this, but it seems as if its libxapians fault doesn't it? best, /p (gdb) bt #0 0x006eb87d in Xapian::Document::Internal::get_value(unsigned int) const () from /usr/lib/sse2/libxapian.so.22 #1 0x006eb952 in Xapian::Document::get_value(unsigned int) const () from /usr/lib/sse2/libxapian.so.22 #2 0x00523963 in notmuch_message_get_date () from /usr/local/lib/libnotmuch.so.1 #3 0x0050c767 in ffi_call_SYSV () from /usr/lib/python2.7/lib-dynload/_ctypes.so #4 0x0050c4bf in ffi_call () from /usr/lib/python2.7/lib-dynload/_ctypes.so #5 0x00504e63 in _ctypes_callproc () from /usr/lib/python2.7/lib-dynload/_ctypes.so #6 0x004fce6e in ?? () from /usr/lib/python2.7/lib-dynload/_ctypes.so #7 0x080a464a in PyObject_Call () #8 0x080dad43 in PyEval_EvalFrameEx () #9 0x080dae8b in PyEval_EvalFrameEx () #10 0x080e11e7 in PyEval_EvalCodeEx () #11 0x08105a61 in ?? () #12 0x080a464a in PyObject_Call () #13 0x080a603f in ?? () #14 0x080a464a in PyObject_Call () #15 0x080da034 in PyEval_CallObjectWithKeywords () #16 0x080a6fff in PyInstance_New () #17 0x080a464a in PyObject_Call () #18 0x080dad43 in PyEval_EvalFrameEx () #19 0x080dae8b in PyEval_EvalFrameEx () #20 0x080dae8b in PyEval_EvalFrameEx () #21 0x080dae8b in PyEval_EvalFrameEx () #22 0x080dae8b in PyEval_EvalFrameEx () #23 0x080e11e7 in PyEval_EvalCodeEx () #24 0x08105a61 in ?? () #25 0x080a464a in PyObject_Call () #26 0x080a603f in ?? () #27 0x080a464a in PyObject_Call () #28 0x080da034 in PyEval_CallObjectWithKeywords () #29 0x080a6fff in PyInstance_New () #30 0x080a464a in PyObject_Call () #31 0x080dad43 in PyEval_EvalFrameEx () #32 0x080dae8b in PyEval_EvalFrameEx () #33 0x080dae8b in PyEval_EvalFrameEx () #34 0x080dae8b in PyEval_EvalFrameEx () #35 0x080dae8b in PyEval_EvalFrameEx () #36 0x080dae8b in PyEval_EvalFrameEx () #37 0x080dae8b in PyEval_EvalFrameEx () #38 0x080e16ee in PyEval_EvalCodeEx () #39 0x080dac2a in PyEval_EvalFrameEx () #40 0x080dae8b in PyEval_EvalFrameEx () #41 0x080dae8b in PyEval_EvalFrameEx () #42 0x080dae8b in PyEval_EvalFrameEx () #43 0x080e11e7 in PyEval_EvalCodeEx () #44 0x080dac2a in PyEval_EvalFrameEx () #45 0x080dae8b in PyEval_EvalFrameEx () #46 0x080e11e7 in PyEval_EvalCodeEx () #47 0x08105a61 in ?? () #48 0x080a464a in PyObject_Call () #49 0x080a603f in ?? () #50 0x080a464a in PyObject_Call () #51 0x080da034 in PyEval_CallObjectWithKeywords () #52 0x080a6fff in PyInstance_New () #53 0x080a464a in PyObject_Call () #54 0x080dad43 in PyEval_EvalFrameEx () #55 0x080dae8b in PyEval_EvalFrameEx () #56 0x080e11e7 in PyEval_EvalCodeEx () #57 0x0812c477 in PyEval_EvalCode () #58 0x0813c010 in ?? () #59 0x08070d09 in PyRun_InteractiveOneFlags () #60 0x08070e0b in PyRun_InteractiveLoopFlags () #61 0x0807124e in PyRun_AnyFileExFlags () #62 0x0805c069 in Py_Main () #63 0x0805b25b in main ()