maybe link to bug https://bugs.freedesktop.org/show_bug.cgi?id=39916 If you go to the Insert->Names->Define menu select a defined name modify the cells's range press button ok or button modify => severe CRASH and need to recover the file works the same if a new file created with 3.4.3 and new defined names or an old file with old names REGRESSION from 3.3.4 you can change the name's range without error or crash in 3.3.4
fixed by eike some days ago in master http://cgit.freedesktop.org/libreoffice/core/commit/?id=792dee46f2b35a21167af182416803c0b80b517c will be in 3.4.4 too
*** Bug 41667 has been marked as a duplicate of this bug. ***
*** This bug has been marked as a duplicate of bug 40571 ***