Version:           1.2.3 (using KDE KDE 3.5.5)
Installed from:    SuSE RPMs
OS:                Linux

One of my users had Kontact running two times, after closing one, it ended up with the backtrace below.

I have it installed on SuSE 10.1, SuSE 10.1 rpm's.

might be a dupe of this one:
https://bugs.kde.org/show_bug.cgi?id=129070
but the crash output is different:

System configuration startup check disabled.

Using host libthread_db library "/lib/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread -1241110864 (LWP 4252)]
[New Thread -1281356896 (LWP 4307)]
[New Thread -1272964192 (LWP 4306)]
[New Thread -1264571488 (LWP 4305)]
[New Thread -1256178784 (LWP 4304)]
[KCrash handler]
#6  0x00000000 in ?? ()
#7  0xb54e0f54 in KMFolder::noContent () from /opt/kde3/lib/libkmailprivate.so
#8  0xb548dbed in KMFolderTree::slotUpdateCounts ()
   from /opt/kde3/lib/libkmailprivate.so
#9  0xb548f0b6 in KMFolderTree::slotUpdateCountTimeout ()
   from /opt/kde3/lib/libkmailprivate.so
#10 0xb5492a53 in KMFolderTree::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#11 0xb6c59f1d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#12 0xb6c5ab7d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#13 0xb6f94d09 in QTimer::timeout () from /usr/lib/qt3/lib/libqt-mt.so.3
#14 0xb6c7d73f in QTimer::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#15 0xb6bfaf07 in QApplication::internalNotify ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#16 0xb6bfbcd1 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#17 0xb72b5bd3 in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#18 0xb6bf0095 in QEventLoop::activateTimers ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#19 0xb6baa8e0 in QEventLoop::processEvents ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#20 0xb6c11d28 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#21 0xb6c11bbe in QEventLoop::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#22 0xb6bfaabf in QApplication::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#23 0x08058c02 in main ()