Do you prefer large outputs, such as that below, in a comment or an attachment? I will keep the gdb session running (since it takes a while to get to the error), so feel free to ask me to investigate further. (gdb) run /usr/bin/bzr branch ~/test.bzr.2/data test2 Starting program: /usr/bin/python /usr/bin/bzr branch ~/test.bzr.2/data test2 [Thread debugging using libthread_db enabled] - Fetching revisions:Get stream source Program received signal SIGSEGV, Segmentation fault. 0x00007ffff2306de8 in create_delta_index () from /usr/lib/python2.6/dist-packages/bzrlib/_groupcompress_pyx.so (gdb) bt #0 0x00007ffff2306de8 in create_delta_index () from /usr/lib/python2.6/dist-packages/bzrlib/_groupcompress_pyx.so #1 0x00007ffff230546c in ?? () from /usr/lib/python2.6/dist-packages/bzrlib/_groupcompress_pyx.so #2 0x00000000004a290d in PyEval_EvalFrameEx () #3 0x00000000004a40e0 in PyEval_EvalCodeEx () #4 0x00000000004a245f in PyEval_EvalFrameEx () #5 0x00000000004a40e0 in PyEval_EvalCodeEx () #6 0x00000000004a245f in PyEval_EvalFrameEx () #7 0x00000000005299ce in ?? () #8 0x000000000049e0ee in PyEval_EvalFrameEx () #9 0x00000000004a2e47 in PyEval_EvalFrameEx () #10 0x00000000004a40e0 in PyEval_EvalCodeEx () #11 0x00000000004a245f in PyEval_EvalFrameEx () #12 0x00000000004a2e47 in PyEval_EvalFrameEx () #13 0x00000000004a2e47 in PyEval_EvalFrameEx () #14 0x00000000004a2e47 in PyEval_EvalFrameEx () #15 0x00000000004a40e0 in PyEval_EvalCodeEx () #16 0x000000000052bf2d in ?? () #17 0x000000000041d6e7 in PyObject_Call () #18 0x00000000004254ff in ?? () #19 0x000000000041d6e7 in PyObject_Call () #20 0x000000000047068e in ?? () ---Type to continue, or q to quit--- #21 0x000000000046b92f in ?? () #22 0x000000000041d6e7 in PyObject_Call () #23 0x00000000004a199c in PyEval_EvalFrameEx () #24 0x00000000004a40e0 in PyEval_EvalCodeEx () #25 0x000000000052bf2d in ?? () #26 0x000000000041d6e7 in PyObject_Call () #27 0x00000000004a0f31 in PyEval_EvalFrameEx () #28 0x00000000004a40e0 in PyEval_EvalCodeEx () #29 0x00000000004a245f in PyEval_EvalFrameEx () #30 0x00000000004a40e0 in PyEval_EvalCodeEx () #31 0x00000000004a245f in PyEval_EvalFrameEx () #32 0x00000000004a40e0 in PyEval_EvalCodeEx () #33 0x00000000004a245f in PyEval_EvalFrameEx () #34 0x00000000004a40e0 in PyEval_EvalCodeEx () #35 0x000000000052bf2d in ?? () #36 0x000000000041d6e7 in PyObject_Call () #37 0x00000000004a0f31 in PyEval_EvalFrameEx () #38 0x00000000004a40e0 in PyEval_EvalCodeEx () #39 0x000000000052bf2d in ?? () #40 0x000000000041d6e7 in PyObject_Call () #41 0x00000000004a0f31 in PyEval_EvalFrameEx () #42 0x00000000004a40e0 in PyEval_EvalCodeEx () #43 0x000000000052bf2d in ?? () ---Type to continue, or q to quit--- #44 0x000000000041d6e7 in PyObject_Call () #45 0x00000000004a0f31 in PyEval_EvalFrameEx () #46 0x00000000004a40e0 in PyEval_EvalCodeEx () #47 0x000000000052bf2d in ?? () #48 0x000000000041d6e7 in PyObject_Call () #49 0x00000000004a0f31 in PyEval_EvalFrameEx () #50 0x00000000004a40e0 in PyEval_EvalCodeEx () #51 0x000000000052be30 in ?? () #52 0x000000000041d6e7 in PyObject_Call () #53 0x00000000004a0f31 in PyEval_EvalFrameEx () #54 0x00000000004a40e0 in PyEval_EvalCodeEx () #55 0x000000000052bf2d in ?? () #56 0x000000000041d6e7 in PyObject_Call () #57 0x00000000004a0f31 in PyEval_EvalFrameEx () #58 0x00000000004a40e0 in PyEval_EvalCodeEx () #59 0x00000000004a245f in PyEval_EvalFrameEx () #60 0x00000000004a2e47 in PyEval_EvalFrameEx () #61 0x00000000004a40e0 in PyEval_EvalCodeEx () #62 0x00000000004a245f in PyEval_EvalFrameEx () #63 0x00000000004a40e0 in PyEval_EvalCodeEx () #64 0x00000000004a41b2 in PyEval_EvalCode () #65 0x00000000004c33a0 in PyRun_FileExFlags () #66 0x00000000004c3564 in PyRun_SimpleFileExFlags () ---Type to continue, or q to quit--- #67 0x0000000000418ab7 in Py_Main () #68 0x00007ffff6fd0abd in __libc_start_main (main=, argc=, ubp_av=, init=, fini=, rtld_fini=, stack_end=0x7fffffffe338) at libc-start.c:220 #69 0x0000000000417ca9 in _start () (gdb)