When I start kmail it immediately crashes and the crash report assistant starts. Unfortunately I cannot complete a bug report using the assistant because it keeps saying 'Could not find debug symbol packages for this application.' when trying to install them. However I get a backtrace (see below).
There are similar bugs listed here, but they seem old like this one:
https://bugs.kde.org/show_bug.cgi?id=301625

Backtrace:

pplication: KMail (kmail), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f3bc9ca4940 (LWP 4920))]

Thread 6 (Thread 0x7f3baffff700 (LWP 5118)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f3bdc18e42b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebKit.so.5
#2  0x00007f3bdc18e469 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebKit.so.5
#3  0x00007f3be0d5a6fa in start_thread (arg=0x7f3baffff700) at pthread_create.c:333
#4  0x00007f3bea04eb5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 5 (Thread 0x7f3bb77fe700 (LWP 5100)):
#0  0x00007f3bdf050ae4 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f3bdf00c24d in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f3bdf00c4ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f3beab8330b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f3beab2dd9a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f3bea953044 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f3bea957c28 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f3be0d5a6fa in start_thread (arg=0x7f3bb77fe700) at pthread_create.c:333
#8  0x00007f3bea04eb5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f3bb7fff700 (LWP 5097)):
#0  0x00007f3bea042e8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f3bdf00c39c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f3bdf00c4ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f3beab8330b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f3beab2dd9a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f3bea953044 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f3bea957c28 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f3be0d5a6fa in start_thread (arg=0x7f3bb7fff700) at pthread_create.c:333
#8  0x00007f3bea04eb5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f3bc5023700 (LWP 5019)):
#0  __libc_disable_asynccancel () at ../sysdeps/unix/sysv/linux/x86_64/cancellation.S:98
#1  0x00007f3bea03e9d9 in read () at ../sysdeps/unix/syscall-template.S:84
#2  0x00007f3bdf04f740 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f3bdf00be84 in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f3bdf00c340 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f3bdf00c4ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007f3beab8330b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f3beab2dd9a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f3bea953044 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f3bea957c28 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007f3be0d5a6fa in start_thread (arg=0x7f3bc5023700) at pthread_create.c:333
#11 0x00007f3bea04eb5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f3bc6257700 (LWP 4933)):
#0  0x00007f3bdf00943c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f3bdf00b8cb in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f3bdf00c2cb in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f3bdf00c4ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f3beab8330b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f3beab2dd9a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f3bea953044 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f3bec9f27a5 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#8  0x00007f3bea957c28 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f3be0d5a6fa in start_thread (arg=0x7f3bc6257700) at pthread_create.c:333
#10 0x00007f3bea04eb5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f3bc9ca4940 (LWP 4920)):
[KCrash Handler]
#6  0x00007f3be77949a4 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#7  0x00007f3be7794f33 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#8  0x00007f3be772b24a in ?? () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#9  0x00007f3be773210c in ?? () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#10 0x00007f3be7720e81 in MessageViewer::Viewer::Viewer(QWidget*, QWidget*, KActionCollection*, QFlags<Qt::WindowType>) () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#11 0x00007f3bec26f485 in KMReaderWin::KMReaderWin(QWidget*, QWidget*, KActionCollection*, QFlags<Qt::WindowType>) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#12 0x00007f3bec2b4bb8 in KMMainWidget::createWidgets() () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#13 0x00007f3bec2be8c8 in KMMainWidget::KMMainWidget(QWidget*, KXMLGUIClient*, KActionCollection*, QExplicitlySharedDataPointer<KSharedConfig>) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#14 0x00007f3bec26c11a in KMMainWin::KMMainWin(QWidget*) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#15 0x00007f3bec27cc8b in KMKernel::openReader(bool) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#16 0x00007f3bec2867c4 in KMKernel::action(bool, bool, QString const&, QString const&, QString const&, QString const&, QString const&, QUrl const&, QList<QUrl> const&, QStringList const&, QString const&, QString const&) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#17 0x00007f3bec287cee in KMKernel::handleCommandLine(bool, QStringList const&, QString const&) () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#18 0x00000000004043f9 in ?? ()
#19 0x0000000000403942 in ?? ()
#20 0x00007f3be9f68830 in __libc_start_main (main=0x402860, argc=1, argv=0x7fff5cb5e258, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff5cb5e248) at ../csu/libc-start.c:291
#21 0x0000000000403ff9 in _start ()

Reproducible: Always

Steps to Reproduce:
1. start kmail
2.
3.

Actual Results:  
Immediate crash, crash report assistant starts


Result when starting kmail by typing 'kmail' on the console:

$ kmail
Pass a valid window to KWallet::Wallet::openWallet().
*** KMail got signal 11 (Exiting)
*** Dead letters dumped.
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kmail path = /usr/bin pid = 6276
KCrash: Arguments: /usr/bin/kmail 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Angehalten              kmail