Recipe: 1) Use i3wm 2) emacs -Q 3) F11 4) M-x ediff 5) Supply 2 files Symptoms: The mini-buffer prints "processing differences.. done.", but the ediff menu is not shown, the buffers don't change and freeze. You can no longer do anything. Hitting C-g four times will send resolve the issue and allow you to defullscreen. The ediff results are then shown. Possible workarounds: Setting (setq ediff-window-setup-function 'ediff-setup-windows-plain) in your configuration file will open the ediff help in the same frame. The issue will then not occur. In GNU Emacs 24.5.1 (i686-pc-linux-gnu, GTK+ Version 3.16.6) of 2015-09-17 on lgw01-50, modified by Debian Windowing system distributor `The X.Org Foundation', version 11.0.11702000 System Description: Ubuntu 15.10 Configured using: `configure --build i686-linux-gnu --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp --build i686-linux-gnu --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp --with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2 -fstack-protector-strong -Wformat -Werror=format-security -Wall' CPPFLAGS=-D_FORTIFY_SOURCE=2 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro'' Important settings: value of $LC_MONETARY: de_DE.UTF-8 value of $LC_NUMERIC: de_DE.UTF-8 value of $LC_TIME: de_DE.UTF-8 value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: ERC Minor modes in effect: diff-auto-refine-mode: t magit-auto-revert-mode: t global-git-commit-mode: t async-bytecomp-package-mode: t erc-list-mode: t erc-menu-mode: t erc-autojoin-mode: t erc-ring-mode: t erc-networks-mode: t erc-pcomplete-mode: t erc-track-mode: t erc-track-minor-mode: t erc-match-mode: t erc-button-mode: t erc-fill-mode: t erc-stamp-mode: t erc-netsplit-mode: t erc-irccontrols-mode: t erc-noncommands-mode: t erc-move-to-prompt-mode: t erc-readonly-mode: t shell-dirtrack-mode: t global-company-mode: t company-mode: t recentf-mode: t electric-pair-mode: t window-numbering-mode: t global-linum-mode: t linum-mode: t global-my-mode: t my-mode: t show-paren-mode: t tooltip-mode: t electric-indent-mode: t mouse-wheel-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 line-number-mode: t transient-mark-mode: t Recent messages: Mark set Quit [2 times] (No files need saving) Active processes exist; kill them and exit anyway? n (No files need saving) Active processes exist; kill them and exit anyway? n is undefined is undefined Mark set byte-code: End of buffer [2 times] Load-path shadows: /home/jpappert/.emacs.d/elpa/helm-20160428.1202/helm-multi-match hides /home/jpappert/.emacs.d/elpa/helm-core-20160515.335/helm-multi-match /usr/share/emacs/24.5/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup /usr/share/emacs24/site-lisp/latex-cjk-thai/thai-word hides /usr/share/emacs/24.5/lisp/language/thai-word Features: (shadow sort mail-extr emacsbug sendmail conf-mode image-file mule-util magit-blame magit-stash magit-bisect magit-remote magit-commit magit-sequence magit magit-apply magit-wip magit-log magit-diff smerge-mode diff-mode magit-core magit-autorevert autorevert filenotify magit-process magit-popup magit-mode help-mode magit-git crm magit-section magit-utils git-commit log-edit message rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev mail-utils gmm-utils mailheader pcvs-util add-log with-editor async-bytecomp async tramp-sh server vc-git face-remap ace-jump-buffer avy bs network-stream starttls tls erc-list erc-menu erc-join erc-ring erc-networks erc-pcomplete erc-track erc-match erc-button erc-fill erc-stamp erc-netsplit erc-goodies erc erc-backend erc-compat jka-compr ediff-merg ediff-wind ediff-diff ediff-mult ediff-help ediff-init ediff-util ediff winner helm-command helm-elisp helm-eval edebug eldoc helm-mode helm-files rx image-dired tramp tramp-compat tramp-loaddefs trampver shell pcomplete format-spec dired-x dired-aux ffap helm-buffers helm-elscreen helm-tags helm-bookmark helm-adaptive helm-info bookmark pp helm-locate helm-external helm-net browse-url xml url url-proxy url-privacy url-expand url-methods url-history url-cookie url-domsuf url-util url-parse auth-source gnus-util mm-util mail-prsvr password-cache url-vars mailcap helm-types company-oddmuse company-keywords company-etags etags company-gtags company-dabbrev-code company-dabbrev company-files company-capf company-cmake company-xcode company-clang company-semantic company-eclim company-template company-css company-nxml company-bbdb company pcase recentf tree-widget wid-edit helm-swoop helm-grep helm-regexp helm-plugin helm-utils compile comint ansi-color ring helm-help elec-pair multiple-cursors mc-hide-unmatched-lines-mode mc-separate-operations rectangular-region-mode mc-mark-pop mc-mark-more thingatpt mc-cycle-cursors mc-edit-lines multiple-cursors-core rect helm cl-macs gv helm-source eieio byte-opt bytecomp byte-compile cl-extra cconv eieio-core helm-multi-match helm-lib dired window-numbering linum solarized-dark-theme solarized dash tex-site info package epg-config reftex reftex-vars easymenu edmacro kmacro cl-loaddefs cl-lib my-mode advice help-fns easy-mmode paren time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-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 nadvice 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 dbusbind gfilenotify dynamic-setting system-font-setting font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs) Memory information: ((conses 8 391370 38161) (symbols 24 43010 0) (miscs 20 1717 666) (strings 16 98456 7951) (string-bytes 1 2731052) (vectors 8 40501) (vector-slots 4 762373 42032) (floats 8 303 673) (intervals 28 3302 830) (buffers 512 34) (heap 1024 20861 4056))