Ok, I've tried again with KDE SC 4.4.0 and it's still there. And it's absolutely trivial to reproduce for me:

-open Kontact
-choose KMail
-open search window in any folder (doesn't matter if local or DIMAP)
-close Kontact
->crash

You don't even need to search or enter any search terms.

*** Bug 227522 has been marked as a duplicate of this bug. ***

*** Bug 229660 has been marked as a duplicate of this bug. ***

reproduced here on kde 4.4.2 under mandriva.

Thread 1 (Thread 0xb317d6d0 (LWP 31705)):
[KCrash Handler]
#6  0xffffe424 in __kernel_vsyscall ()
#7  0xb4a51a81 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#8  0xb4a533d2 in abort () at abort.c:92
#9  0xb4a4ab08 in __assert_fail (assertion=0xafd476b8 "mySelf", file=0xafd4709c "/home/niconico/SVN/4.4/kdepim/kmail/kmkernel.cpp", line=2320, function=
    0xafd489c0 "static KSharedPtr<KSharedConfig> KMKernel::config()") at assert.c:81
#10 0xafacd958 in KMKernel::config () at /home/niconico/SVN/4.4/kdepim/kmail/kmkernel.cpp:2320
#11 0xafafae41 in KMail::SearchWindow::~SearchWindow (this=0xa9ec5c8, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at /home/niconico/SVN/4.4/kdepim/kmail/searchwindow.cpp:386

(In reply to comment #1)
> Ok, I've tried again with KDE SC 4.4.0 and it's still there. And it's
> absolutely trivial to reproduce for me:
> 
> -open Kontact
> -choose KMail
> -open search window in any folder (doesn't matter if local or DIMAP)
> -close Kontact
> ->crash
> 
> You don't even need to search or enter any search terms.

Same here. I can also add that none IMAP transaction get completed if I search for a message.
Kontact 4.3.5
Kmail 1.12.4
KDE 4.3.5
Kubuntu Packages 9.10
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#6  0x02bdffd0 in KSharedPtr<KSharedConfig>::operator bool () at /usr/include/ksharedptr.h:106
#7  KMKernel::config () at ../../kmail/kmkernel.cpp:2284
#8  0x02c1430f in ~SearchWindow (this=0x9f54010, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at ../../kmail/searchwindow.cpp:387
#9  0x00d9c135 in qDeleteInEventHandler (o=0x0) at kernel/qobject.cpp:3815
#10 0x00d9d62b in QObject::event (this=0x9f54010, e=0x9a82e80) at kernel/qobject.cpp:1094
#11 0x01056906 in QWidget::event (this=0x9f54010, event=0x9a82e80) at kernel/qwidget.cpp:7946
#12 0x01001f54 in QApplicationPrivate::notify_helper (this=0x9616910, receiver=0x9f54010, e=0x9a82e80) at kernel/qapplication.cpp:4056
#13 0x010095ca in QApplication::notify (this=0xbffaf074, receiver=0x9f54010, e=0x9a82e80) at kernel/qapplication.cpp:4021
#14 0x0073825a in KApplication::notify (this=0xbffaf074, receiver=0x9f54010, event=0x9a82e80) at ../../kdeui/kernel/kapplication.cpp:302
#15 0x00d8d6cb in QCoreApplication::notifyInternal (this=0xbffaf074, receiver=0x9f54010, event=0x9a82e80) at kernel/qcoreapplication.cpp:610
#16 0x00d8e2b2 in QCoreApplication::sendEvent (receiver=0x0, event_type=0, data=0x95e8820) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#17 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x95e8820) at kernel/qcoreapplication.cpp:1247
#18 0x00d8e47d in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1140
#19 0x00db83ff in QCoreApplication::sendPostedEvents (s=0x9611b90) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#20 postEventSourceDispatch (s=0x9611b90) at kernel/qeventdispatcher_glib.cpp:210
#21 0x049b1e88 in g_main_dispatch (context=0x9611b10) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:1960
#22 IA__g_main_context_dispatch (context=0x9611b10) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2513
#23 0x049b5730 in g_main_context_iterate (context=0x9611b10, block=<value optimized out>, dispatch=1, self=0x96073c0) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2591
#24 0x049b5863 in IA__g_main_context_iteration (context=0x9611b10, may_block=1) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2654
#25 0x00db802c in QEventDispatcherGlib::processEvents (this=0x95e89f8, flags=...) at kernel/qeventdispatcher_glib.cpp:327
#26 0x010a2be5 in QGuiEventDispatcherGlib::processEvents (this=0x95e89f8, flags=...) at kernel/qguieventdispatcher_glib.cpp:202
#27 0x00d8bc79 in QEventLoop::processEvents (this=0xbffaefd4, flags=) at kernel/qeventloop.cpp:149
#28 0x00d8c0ca in QEventLoop::exec (this=0xbffaefd4, flags=...) at kernel/qeventloop.cpp:201
#29 0x00d8e53f in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#30 0x01001dd7 in QApplication::exec () at kernel/qapplication.cpp:3525
#31 0x0804b4e6 in main (argc=1, argv=0xbffaf294) at ../../../kontact/src/main.cpp:218

Created attachment 43704 [details]
New crash information added by DrKonqi

Kontact crashed after I tryed to close it.

Created attachment 51697 [details]
New crash information added by DrKonqi

Closed Kontact after failing to load an entry in Contact list.

Created attachment 52383 [details]
New crash information added by DrKonqi

kontact (4.4.6) on KDE Platform 4.5.1 (KDE 4.5.1) using Qt 4.7.0

- What I was doing when the application crashed:

Same situation here, the backtrace just looks a little different.

-- Backtrace (Reduced):
#7  0xb2fbcbb3 in KSharedPtr<KSharedConfig>::operator bool () at /usr/include/ksharedptr.h:106
#8  KMKernel::config () at ../../kmail/kmkernel.cpp:2321
#9  0xb2ff5821 in ~SearchWindow (this=0xa355da0, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at ../../kmail/searchwindow.cpp:386
#10 0x03d67dc5 in qDeleteInEventHandler (o=0x0) at kernel/qobject.cpp:3988
#11 0x03d69ae8 in QObject::event (this=0xa355da0, e=0xbfe3b7cc) at kernel/qobject.cpp:1202

*** Bug 262430 has been marked as a duplicate of this bug. ***

(In reply to comment #1)
> Ok, I've tried again with KDE SC 4.4.0 and it's still there. And it's
> absolutely trivial to reproduce for me:
> 
> -open Kontact
> -choose KMail
> -open search window in any folder (doesn't matter if local or DIMAP)
> -close Kontact
> ->crash
> 
> You don't even need to search or enter any search terms.

I can't reproduce the crash with these steps in KDEPIM master.
Even changing the active plugin before quitting Kontact had no effect.

I will wager that you are testing with an empty or near empty mail
system and the bug reporter has thousands of mail messages which have
been migrated forward from version to version plus new stuff.

Because KDEPim doesn't have a complete backup/restore built into it like
Evolution, it becomes worthless to people who actually USE their desktop
for something other than distro hopping or distro development.  I,
myself, am running Evolution on KDE because migration is impossible with
KDEPIM.  It perpetually loses chunks of address information and the
developers thing everyone should know which super secret file to copy
where.  That Akondi (or whatever) was a God-foresaken mis-step.

(In reply to comment #12)
> I will wager that you are testing with an empty or near empty mail
> system and the bug reporter has thousands of mail messages which have
> been migrated forward from version to version plus new stuff.
> 

Depends what you call empty. The KMail version I'm currently running has 4 email accounts configured and a bit more than 40000 messages stored.

I have only one email account, but I have folders with more than 4000
messages.  My email has migrated forward through many different versions
of both Ubuntu and OpenSuSE and I have quite a few messages from pre-Y2K
because they are still historically relevant.

I gave up on KDEPim and will soon be forced to give up on KDE because of
the way Evolution works on it, all because there isn't a clean
backup/restore for the entire PIM like there is with Evolution.

I'm willing to bet the bulk of this user's problem stems from the
completely undocumented half-arsed methods of migrating email forward
via KDEPIM.  That "copy your home directory, then restore after install"
trashes sooooooooooooooooooooooooo many things.  Because you don't have
a guaranteed-to-work-backup-and-restore-migration-utility built into the
product, the odds of getting them to wipe and clean install are null.
The "clean install" will most likely involve copying some files around
to save things, which is where the problem was created in the first
place.

Created attachment 56067 [details]
New crash information added by DrKonqi

kontact (4.4.8) on KDE Platform 4.5.4 (KDE 4.5.4) using Qt 4.6.3

- What I was doing when the application crashed:

I followed the steps in comment 1, in a folder belonging to a (gmail) IMAP account.  Regarding comment 11, did you have any IMAP accounts?

-- Backtrace (Reduced):
#6  0x0000003339a98787 in operator bool () at /usr/include/kde4/ksharedptr.h:106
#7  KMKernel::config () at /usr/src/debug/kdepim-4.4.8/kmail/kmkernel.cpp:2320
#8  0x0000003339ac7070 in KMail::SearchWindow::~SearchWindow (this=0x2da1990, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>)
    at /usr/src/debug/kdepim-4.4.8/kmail/searchwindow.cpp:386
#9  0x0000003339ac7409 in KMail::SearchWindow::~SearchWindow (this=0x2da1990, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>)
    at /usr/src/debug/kdepim-4.4.8/kmail/searchwindow.cpp:395
#10 0x000000331fb62f55 in QObject::event (this=0x2da1990, e=0x31d2770) at kernel/qobject.cpp:1231

(In reply to comment #15)
> kontact (4.4.8) on KDE Platform 4.5.4 (KDE 4.5.4) using Qt 4.6.3
> 

It would be interesting to know if someone can reproduce the crash with a recent kdepim 4.6 beta version.

Works for me with KDEpim 4.6 beta

*** Bug 269845 has been marked as a duplicate of this bug. ***

*** Bug 270774 has been marked as a duplicate of this bug. ***

Closing then. Thanks for the feedback.

*** Bug 282871 has been marked as a duplicate of this bug. ***

Clearing the CC list. The issue is fixed in kdepim > 4.6