After upgrading to macOS Catalina, Emacs (v26.3 from GNU Emacs for Mac OS X) works very strange. Without Emacs already running, Finder can open a file with Emacs as usual. But once Emacs.app is running, it cannot any longer. For example, double clicking the file on Finder window does nothing; no error message, either. Opening a file from Emacs GUI causes no problem. Drag-ang-drop'ing a file onto Emacs also works fine. Best regards, Masso %%%% In GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.2.0, NS appkit-1671.20 Version 10.14.3 (Build 18D109)) of 2019-09-02 built on builder10-14.porkrind.org Windowing system distributor 'Apple', version 10.3.1894 Recent messages: Loading /Users/Masso/Tower/Emacs/Preferences.el (source)... Loading ‘web-mode’: unescaped character literals `?]' detected! Loading /Users/Masso/Tower/Emacs/Preferences.el (source)...done Loading /Users/Masso/Tower/Emacs/Customizations.el (source)...done For information about GNU Emacs and the GNU system, type C-h C-a. Loading dired-x...done Loading dired-aux...done Configured using: 'configure --with-ns '--enable-locallisppath=/Library/Application Support/Emacs/${version}/site-lisp:/Library/Application Support/Emacs/site-lisp' --with-modules' Configured features: NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES THREADS Important settings: value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: Text Minor modes in effect: global-undo-tree-mode: t undo-tree-mode: t show-paren-mode: t delete-selection-mode: t global-eldoc-mode: t electric-indent-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 global-visual-line-mode: t visual-line-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message rmc puny dired-aux dired-x dired dired-loaddefs format-spec rfc822 mml mml-sec epa epg gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils Preferences server web-mode advice derived edmacro kmacro disp-table bibwiz refley texson undo-tree diff buffet ls-lisp seeker basil apple aurora keys paren delsel cua-base deeper-blue-theme finder-inf info tex-site package easymenu epg-config url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib time-date tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win ucs-normalize mule-util term/common-win tool-bar dnd fontset image regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese composite charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer cl-preloaded 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 threads kqueue cocoa ns multi-tty make-network-process emacs) Memory information: ((conses 16 284274 11043) (symbols 48 24080 2) (miscs 40 50 252) (strings 32 44149 2072) (string-bytes 1 1156678) (vectors 16 39426) (vector-slots 8 774132 9466) (floats 8 73 63) (intervals 56 224 0) (buffers 992 11))