I noticed this when using password-store.el[1] which I use to look up passwords using pass[2] The file hasn't been updated since 2015 and I know it's been working so I assume a recent change caused this. Merely putting "x" instead of "" as the argument works fine. [1] https://git.zx2c4.com/password-store/tree/contrib/emacs [2] https://www.passwordstore.org/ Steps to reproduce Starting from emacs -Q: M-: (make-temp-file "") ;; Debugger entered--Lisp error: (file-error "Creating file with prefix" "Permission denied" "/tmp") ;; make-temp-file-internal("/tmp" nil "") ;; make-temp-file("") ;; eval((make-temp-file "") nil) ;; eval-expression((make-temp-file "") nil nil 127) In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.18) of 2017-08-13 built on agro Repository revision: a6ad98ad66e1d0c0dac5f25ba91e11d0cf9da725 Windowing system distributor 'The X.Org Foundation', version 11.0.11903000 System Description: Arch Linux Recent messages: For information about GNU Emacs and the GNU system, type C-h C-a. Entering debugger... Back to top level Configured using: 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games --with-sound=alsa --with-xft --with-modules --with-x-toolkit=gtk3 --without-gconf --without-gsettings --without-gpm --without-m17n-flt --with-xwidgets --without-compress-install 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now' Configured features: XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS NOTIFY ACL GNUTLS LIBXML2 FREETYPE LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 MODULES XWIDGETS LIBSYSTEMD Important settings: value of $LC_COLLATE: C value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t global-eldoc-mode: t eldoc-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-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 line-number-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message subr-x puny seq dired dired-loaddefs format-spec rfc822 mml mml-sec password-cache epa derived epg epg-config 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 help-mode easymenu cl-print byte-opt gv bytecomp byte-compile cl-loaddefs cl-lib cconv debug time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win term/common-win x-dnd 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 dbusbind inotify dynamic-setting font-render-setting xwidget-internal move-toolbar gtk x-toolkit x multi-tty make-network-process emacs) Memory information: ((conses 16 96356 5925) (symbols 48 20459 1) (miscs 40 48 104) (strings 32 29164 1340) (string-bytes 1 770963) (vectors 16 14155) (vector-slots 8 491071 8271) (floats 8 51 65) (intervals 56 237 0) (buffers 992 12)) -- Best regards, Benny 0x9EC76EA52B8F32A1 6315 887D 6E46 6967 7AC0 3E76 9EC7 6EA5 2B8F 32A1