I'm trying to set up the python-mode (python.el) to use ipython as the interactive shell. I've added the folloging lines in my .emacs file: (require 'python) (setq python-shell-interpreter "C:/Python27/python.exe" python-shell-interpreter-args "-i C:/Python27/Scripts/ipython-script.py console --matplotlib=tk" ;; python-shell-interpreter-args ;; "-i C:/Python27/Scripts/ipython-script.py console --matplotlib=qt" python-shell-prompt-regexp "In \\[[0-9]+\\]: " python-shell-prompt-output-regexp "Out\\[[0-9]+\\]: " python-shell-completion-setup-code "from IPython.core.completerlib import module_completion" python-shell-completion-module-string-code "';'.join(module_completion('''%s'''))\n" python-shell-completion-string-code "';'.join(get_ipython().Completer.all_completions('''%s'''))\n") My python installation is Python(x,y) 2.7.6 (the most recent distribution). I'm having INTERMITTENT problems starting a python shell process (either with run-python or with C-c C-z in a python program source file) while specifying to use the qt backend for matplotlib. Sometimes everything just runs smoothly, but often the new python shell window appears as follows: Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] Type "copyright", "credits" or "license" for more information. IPython 1.2.0 -- An enhanced Interactive Python. ? -> Introduction and overview of IPython's features. %quickref -> Quick reference. help -> Python's own help system. object? -> Details about 'object', use 'object??' for extra details. In [1]: In [2]: and freezes: no response to whatever command. I just have to kill the buffer. Note that when the process starts correctly I get 4 input prompts (In [1]:\n In [2]:\n In [3]:\n In [4]:\n). The problem happens starting emacs with -Q as well. This does not happen if I use tk as the backend for matplotlib and everything works fine. Everything works fine outside of emacs as well (in a console) with both matplotlib backends. I've checked and confirmed the problem on two different machines running Windows 7 (one with the Ultimate and the other with the Enterprise variant). If Emacs crashed, and you have the Emacs process in the gdb debugger, please include the output from the following gdb commands: `bt full' and `xbacktrace'. For information about debugging Emacs, please read the file c:/Program Files (x86)/emacs-24.3/etc/DEBUG. In GNU Emacs 24.3.1 (i386-mingw-nt6.1.7601) of 2013-03-17 on MARVIN Windowing system distributor `Microsoft Corp.', version 6.1.7601 Configured using: `configure --with-gcc (4.7) --cflags -ID:/devel/emacs/libs/libXpm-3.5.8/include -ID:/devel/emacs/libs/libXpm-3.5.8/src -ID:/devel/emacs/libs/libpng-dev_1.4.3-1/include -ID:/devel/emacs/libs/zlib-dev_1.2.5-2/include -ID:/devel/emacs/libs/giflib-4.1.4-1/include -ID:/devel/emacs/libs/jpeg-6b-4/include -ID:/devel/emacs/libs/tiff-3.8.2-1/include -ID:/devel/emacs/libs/gnutls-3.0.9/include -ID:/devel/emacs/libs/libiconv-1.13.1-1-dev/include -ID:/devel/emacs/libs/libxml2-2.7.8/include/libxml2' Important settings: value of $LANG: ENU locale-coding-system: cp1252 default enable-multibyte-characters: t Major mode: Python Minor modes in effect: jedi-mode: t auto-complete-mode: t tooltip-mode: t mouse-wheel-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t column-number-mode: t line-number-mode: t transient-mark-mode: t Recent input: C-c C-z y C-x o C-x C-f c : / p r o SPC f SPC e m 3 s i s i d f C-SPC M-x c o m m e r e C-SPC M-x u n c o m C-x C-s C-x k M-x r e p o r Recent messages: Sent python-shell-completion-setup-code Sent python-ffap-setup-code Sent python-eldoc-setup-code Mark set [2 times] Making completion list... Mark set Saving file c:/Program Files (x86)/emacs-24.3/site-lisp/site-start.d/fbe.el... Cannot write backup file; backing up in ~\.emacs.d\%backup%~ Wrote c:/Program Files (x86)/emacs-24.3/site-lisp/site-start.d/fbe.el Making completion list... [3 times] Load-path shadows: None found. Features: (shadow sort flyspell ispell mail-extr emacsbug message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mail-utils help-mode compile network-stream auth-source eieio byte-opt bytecomp byte-compile cconv gnus-util mm-util mail-prsvr password-cache starttls tls warnings advice advice-preload jedi help-fns easy-mmode python-environment auto-complete cl-macs gv popup epc ctable edmacro kmacro concurrent deferred cl cl-lib server preview-latex python rx easymenu comint ring ansi-color jedi-autoloads auto-complete-autoloads epc-autoloads ctable-autoloads concurrent-autoloads popup-autoloads finder-inf python-environment-autoloads deferred-autoloads package tex-site auto-loads time-date tooltip ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process w32 multi-tty emacs)