NOTE: This patch has been committed. That's what you say when you discover a bug like this. Definitely goes in 21.4. lisp/ChangeLog addition: 2004-12-11 Ben Wing <ben(a)xemacs.org&gt; * files.el (find-coding-system-magic-cookie-in-file): File positions are 0 based not 1 based. build source patch: Diff command: bash -ci "cvs-diff --show-c-function -no-changelog " Files affected: lisp/files.el Index: lisp/files.el =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/lisp/files.el,v retrieving revision 1.70 diff -u -p -r1.70 files.el --- lisp/files.el 2004/06/06 23:58:44 1.70 +++ lisp/files.el 2004/12/12 02:44:25 ＠＠ -2107,7 +2107,7 ＠＠ ISO 2022 encoding of most non-ASCII char (save-excursion (with-temp-buffer (let ((coding-system-for-read 'raw-text)) - (insert-file-contents file nil 1 3001)) + (insert-file-contents file nil 0 3000)) (goto-char (point-min)) (or (and (looking-at "^[^\n]*-\\*-[^\n]*coding: \\([^ \t\n;]+\\)[^\n]*-\\*-")