KDEが初期ロード後にログインページにリダイレクトされるのはなぜですか？

Debian Jessieを新しくインストールしてKDEをインストールしようとしていますが、ログインしてデスクトップ環境にプラズマを選択すると、数秒間プラズマブート画面に行き、すぐに通常のログイン画面に戻ります。 。この問題をどのように解決できますか？どこを見ますか？

私のファイルの内容は.xsession-errors次のとおりです。

Xsession: X session started for nathan at Thu Oct 29 00:56:25 MDT 2015
localuser:nathan being added to access control list
Loading stage  "initial" 193
startkde: Starting up...
kdeinit5: preparing to launch 'libkdeinit5_klauncher'
kdeinit5: Launched KLauncher, pid = 950, result = 0
Qt: Session management error: networkIdsList argument is NULL
Connecting to deprecated signal  QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
kdeinit5: opened connection to :1
kdeinit5: preparing to launch 'libkdeinit5_kded5'
kdeinit5: Launched KDED, pid = 952 result = 0
kdeinit5: preparing to launch 'libkdeinit5_kcminit_startup'
kdeinit5: Launched 'kcminit_startup', pid = 953 result = 0
Qt: Session management error: networkIdsList argument is NULL
Recreating ksycoca file ("/home/nathan/.cache  /ksycoca5_en_ABGG1sD7FGwLWpevNW74RXeZhv0=", version 303)
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kdeinit5 path = /usr/bin pid = 952
KCrash: Arguments: /usr/bin/kdeinit5
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi   from kdeinit
kdeinit5: Got EXEC_NEW '/usr/lib/x86_64-linux-gnu/libexec/drkonqi' from wrapper.
kdeinit5: preparing to launch '/usr/lib/x86_64-linux-gnu/libexec/drkonqi'
kdeinit5: PID 957 terminated.
Menu "applications-kmenuedit.menu" not found.
Saving
kdeinit5: Got SETENV 'KDE_MULTIHEAD=false' from launcher.
Initializing  "kcm_input" :  "kcminit_mouse"
kdeinit5: PID 953 terminated.
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kdeinit5 path = /usr/bin pid = 954
KCrash: Arguments: /usr/bin/kdeinit5
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi   from kdeinit
kdeinit5: Got EXEC_NEW '/usr/lib/x86_64-linux-gnu/libexec/drkonqi' from   wrapper.
kdeinit5: preparing to launch '/usr/lib/x86_64-linux-gnu/libexec/drkonqi'
kdeinit5: Got KWRAPPER 'ksmserver' from wrapper.
kdeinit5: preparing to launch 'libkdeinit5_ksmserver'
kdeinit5: PID 952 terminated.
kdeinit5: PID 960 terminated.
Qt: Session management error: networkIdsList argument is NULL
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kdeinit5 path = /usr/bin pid = 961
KCrash: Arguments: /usr/bin/kdeinit5
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi   from kdeinit
kdeinit5: Got EXEC_NEW '/usr/lib/x86_64-linux-gnu/libexec/drkonqi' from   wrapper.
kdeinit5: preparing to launch '/usr/lib/x86_64-linux-gnu/libexec/drkonqi'
kdeinit5: PID 964 terminated.
kdeinit5: PID 961 terminated.
startkde: Shutting down...
kdeinit5: terminate KDE.
klauncher: Exiting on signal 1
startkde: Running shutdown scripts...
startkde: Done.