Version:            (using Devel)
OS:                Linux
Installed from:    Compiled sources

KMail svn 902265: having no SMTP account configured, you are still able to press the send button, and then kmail crashes:

Thread 2 (Thread 0x41d8a950 (LWP 23574)):
#0  0x00000039f46c8ce2 in select () from /lib/libc.so.6
#1  0x0000003e7f334746 in QProcessManager::run (this=<value optimized out>) at io/qprocess_unix.cpp:301
#2  0x0000003e7f26c162 in QThreadPrivate::start (arg=<value optimized out>) at thread/qthread_unix.cpp:185
#3  0x00000039f5206fc7 in start_thread () from /lib/libpthread.so.0
#4  0x00000039f46cf5ad in clone () from /lib/libc.so.6
#5  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f17f23a36f0 (LWP 23506)):
#0  0x0000000000000000 in ?? ()
#1  0x0000003a1a414f70 in GpgME::Context::cancelPendingOperation (this=<value optimized out>)
    at ../../gpgme++/context.cpp:789
#2  0x0000003a1ac8a3e1 in do_list_keys (ctx=<value optimized out>, pats=<value optimized out>,
    keys=<value optimized out>, secretOnly=<value optimized out>)
    at ../../libkleo/backends/qgpgme/qgpgmekeylistjob.cpp:80
#3  0x0000003a1ac8b3b5 in list_keys (ctx=<value optimized out>, pats=<value optimized out>,
    secretOnly=<value optimized out>) at ../../libkleo/backends/qgpgme/qgpgmekeylistjob.cpp:87
#4  0x0000003a1ac8b750 in Kleo::QGpgMEKeyListJob::exec (this=<value optimized out>,
    patterns=<value optimized out>, secretOnly=<value optimized out>, keys=<value optimized out>)
    at ../../libkleo/backends/qgpgme/qgpgmekeylistjob.cpp:133
#5  0x0000003a1c461633 in Kleo::KeyResolver::lookup (this=<value optimized out>,
    patterns=<value optimized out>, secret=<value optimized out>) at ../../kmail/keyresolver.cpp:1502
#6  0x0000003a1c463ca2 in Kleo::KeyResolver::getEncryptionKeys (this=<value optimized out>,
    person=<value optimized out>, quiet=<value optimized out>) at ../../kmail/keyresolver.cpp:1450
#7  0x0000003a1c4642ab in Kleo::KeyResolver::EncryptionPreferenceCounter::operator() (
    this=<value optimized out>, item=<value optimized out>) at ../../kmail/keyresolver.cpp:386
#8  0x0000003a1c464457 in Kleo::KeyResolver::checkEncryptionPreferences (this=<value optimized out>,
    encryptionRequested=<value optimized out>) at /usr/include/c++/4.3/bits/stl_algo.h:3791
#9  0x0000003a1c45739e in MessageComposer::determineWhetherToEncrypt (this=<value optimized out>,
    doEncryptCompletely=<value optimized out>) at ../../kmail/messagecomposer.cpp:890
#10 0x0000003a1c45a130 in MessageComposer::adjustCryptFlags (this=<value optimized out>)
    at ../../kmail/messagecomposer.cpp:761
#11 0x0000003a1c44602f in MessageComposer::slotDoNextJob (this=<value optimized out>)
    at ../../kmail/messagecomposer.cpp:430
#12 0x0000003a1c4460fd in MessageComposer::qt_metacall (this=<value optimized out>, _c=<value optimized out>,
    _id=<value optimized out>, _a=<value optimized out>) at ./messagecomposer.moc:69
#13 0x0000003e7f3686d4 in QMetaObject::activate (sender=<value optimized out>,
    from_signal_index=<value optimized out>, to_signal_index=<value optimized out>,
    argv=<value optimized out>) at kernel/qobject.cpp:3031
#14 0x0000003e7f36e93f in QSingleShotTimer::timerEvent (this=<value optimized out>) at kernel/qtimer.cpp:294
#15 0x0000003e7f362fe3 in QObject::event (this=<value optimized out>, e=<value optimized out>)
    at kernel/qobject.cpp:1120
#16 0x0000003e80bcaa5d in QApplicationPrivate::notify_helper (this=<value optimized out>,
    receiver=<value optimized out>, e=<value optimized out>) at kernel/qapplication.cpp:3803
#17 0x0000003e80bd27da in QApplication::notify (this=<value optimized out>, receiver=<value optimized out>,
    e=<value optimized out>) at kernel/qapplication.cpp:3768
#18 0x0000003a13624f6b in KApplication::notify (this=<value optimized out>, receiver=<value optimized out>,
    event=<value optimized out>) at ../../kdeui/kernel/kapplication.cpp:307
#19 0x0000003e7f354381 in QCoreApplication::notifyInternal (this=<value optimized out>,
    receiver=<value optimized out>, event=<value optimized out>) at kernel/qcoreapplication.cpp:587
#20 0x0000003e7f380256 in QTimerInfoList::activateTimers (this=<value optimized out>)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:209
#21 0x0000003e7f37c7ad in timerSourceDispatch (source=<value optimized out>)
    at kernel/qeventdispatcher_glib.cpp:160
#22 0x0000003e7e63978b in IA__g_main_context_dispatch (context=<value optimized out>)
    at /build/buildd/glib2.0-2.16.6/glib/gmain.c:2012
#23 0x0000003e7e63cf5d in g_main_context_iterate (context=<value optimized out>, block=<value optimized out>,
    dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.16.6/glib/gmain.c:2645
#24 0x0000003e7e63d11b in IA__g_main_context_iteration (context=<value optimized out>,
    may_block=<value optimized out>) at /build/buildd/glib2.0-2.16.6/glib/gmain.c:2708
#25 0x0000003e7f37c70f in QEventDispatcherGlib::processEvents (this=<value optimized out>,
    flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:319
#26 0x0000003e80c5c44f in QGuiEventDispatcherGlib::processEvents (this=<value optimized out>,
    flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:198
#27 0x0000003e7f352ca2 in QEventLoop::processEvents (this=<value optimized out>, flags=<value optimized out>)
    at kernel/qeventloop.cpp:143
#28 0x0000003e7f352e2d in QEventLoop::exec (this=<value optimized out>, flags=<value optimized out>)
    at kernel/qeventloop.cpp:194
#29 0x0000003e7f3552dd in QCoreApplication::exec () at kernel/qcoreapplication.cpp:845
#30 0x0000000000402f8b in main (argc=<value optimized out>, argv=<value optimized out>)
    at ../../kmail/main.cpp:146