Version: 1.10.0 (using 4.1.00 (KDE 4.1.0), Kubuntu packages) Compiler: gcc OS: Linux (i686) release 2.6.24-19-generic When adding a new label in KMail KDE4.1 via Preferences->Mail view->Labels (or is it Categories in English? using German KDE here), once you press "Apply" or "OK" KMail instantly crashes and not even KDebug comes up...
Does kmail print something on the shell (start it from the shell) ???
It doesn't crash for me, have you got better instructions on how to repreoduce? Try running KMail under GDB to get a useful backtrace, see http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports#Retrieving_a_backtrace_with_GDB
No backtrace was provided (Comment #2). Closing.