If you can reproduce the crash at will, may you read http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports and post a complete backtrace here? 
You need to install the "kdepim-debuginfo" package
Thanks :)

I have the same problem on openSuse 11.1 x64 with KDE 4.2.2. (on my i386 Laptop, everything works fine).

On Akonadi startup, the Akonadi ical resource crashes (I get the crash dialog at least four times whenever I log into KDE). The changes I make in KOrganizer are not saved in the *.ics file that is connected with Akonadi.

Here's the backtrace:

Anwendung: Akonadi Resource (akonadi_ical_resource), Signal SIGABRT
0x00007f4c2d455cb0 in nanosleep () from /lib64/libc.so.6
[Current thread is 1 (Thread 0x7f4c31717750 (LWP 18312))]

Thread 1 (Thread 0x7f4c31717750 (LWP 18312)):
[KCrash Handler]
#5  0x00007f4c2d3e6645 in raise () from /lib64/libc.so.6
#6  0x00007f4c2d3e7c33 in abort () from /lib64/libc.so.6
#7  0x00007f4c2ee612d5 in qt_message_output(QtMsgType, char const*) () from /usr/lib64/libQtCore.so.4
#8  0x00007f4c2ee6141d in qFatal(char const*, ...) () from /usr/lib64/libQtCore.so.4
#9  0x000000000040f44a in _start ()

@J: your crash information seems to be different. As you can reproduce the issue a lot of times, can you install the "kdepim4-debuginfo" and "akonadi-debug"(or something like that) packages in order to get a completer backtrace and post it in a NEW report?
Thanks a lot

Marking as NEEDSINFO as the original reporter didn't replied.

(In reply to comment #3)
> @J: your crash information seems to be different. As you can reproduce the
> issue a lot of times, can you install the "kdepim4-debuginfo" and
> "akonadi-debug"(or something like that) packages in order to get a completer
> backtrace and post it in a NEW report?
> Thanks a lot

done:
http://bugs.kde.org/show_bug.cgi?id=190691

I am on Kubuntu 9.04 and having BIG problems with a lot of sigsev crashes today.

It MIGHT be because I have an IMAP connection to Gmail. I will try to reboot and start Kmail again, then delete the Gmail account and see if that helps. Here is the crash report:

Application: KMail (kmail), signal SIGSEGV

Thread 1 (Thread 0xb3bd5b40 (LWP 7587)):
[KCrash Handler]
#6  0xb67459a7 in QTreeWidget::setItemExpanded () from /usr/lib/libQtGui.so.4
#7  0xb72dbf8c in KMail::FolderView::slotFolderExpanded () from /usr/lib/libkmailprivate.so.4
#8  0xb72e7ee5 in KMail::FolderView::qt_metacall () from /usr/lib/libkmailprivate.so.4
#9  0xb72ec10a in ?? () from /usr/lib/libkmailprivate.so.4
#10 0xb5eb5ca8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#11 0xb5eb6932 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#12 0xb673d113 in QTreeWidget::itemExpanded () from /usr/lib/libQtGui.so.4
#13 0xb6742446 in ?? () from /usr/lib/libQtGui.so.4
#14 0xb674a7ff in QTreeWidget::qt_metacall () from /usr/lib/libQtGui.so.4
#15 0xb70d34da in KPIM::TreeWidget::qt_metacall () from /usr/lib/libkdepim.so.4
#16 0xb70d367a in KPIM::FolderTreeWidget::qt_metacall () from /usr/lib/libkdepim.so.4
#17 0xb72e7e8a in KMail::FolderView::qt_metacall () from /usr/lib/libkmailprivate.so.4
#18 0xb72ec10a in ?? () from /usr/lib/libkmailprivate.so.4
#19 0xb5eb5ca8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#20 0xb5eb6932 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#21 0xb66fe4f3 in QTreeView::expanded () from /usr/lib/libQtGui.so.4
#22 0xb670fdee in QTreeView::expand () from /usr/lib/libQtGui.so.4
#23 0xb671091c in QTreeView::setExpanded () from /usr/lib/libQtGui.so.4
#24 0xb6745a2c in QTreeWidget::setItemExpanded () from /usr/lib/libQtGui.so.4
#25 0xb72e0d1c in KMail::FolderView::restoreItemStates () from /usr/lib/libkmailprivate.so.4
#26 0xb72e7a7d in KMail::FolderView::reload () from /usr/lib/libkmailprivate.so.4
#27 0xb756a906 in KMMainWidget::readConfig () from /usr/lib/libkmailprivate.so.4
#28 0xb7580850 in KMMainWidget::KMMainWidget () from /usr/lib/libkmailprivate.so.4
#29 0xb7264abe in ?? () from /usr/lib/libkmailprivate.so.4
#30 0xb7487951 in KMKernel::openReader () from /usr/lib/libkmailprivate.so.4
#31 0xb74896c4 in KMKernel::action () from /usr/lib/libkmailprivate.so.4
#32 0xb748a96f in KMKernel::handleCommandLine () from /usr/lib/libkmailprivate.so.4
#33 0x0804af8d in _start ()

@Oceanwatcher: your crash seems more like bug 190599

Not so sure. I had a password stored and it was working ok until I added some POP3 accounts.

I really love many things in Kmail. But it seems a bit unstable and unfinished.

*** This bug has been marked as a duplicate of bug 184324 ***