Today's cvs for 21.5, Redhat 6.2. No init.el or .emacs, start a fresh xemacs, setup some things through the menus and custom and save the options so that you get a custom.el with: (custom-set-variables '(gutter-buffers-tab-visible-p t) '(paren-mode (quote blink-paren) nil (paren)) '(column-number-mode t) '(enabled-behavior-list (quote (resize-minibuffer recent-files mwheel jka-compr func-menu filladapt efs))) '(pending-delete-mode t nil (pending-del)) '(toolbar-visible-p nil) '(line-number-mode t) '(user-mail-address &quot;galibert(a)pobox.com&quot;) '(query-user-mail-address nil)) (custom-set-faces '(default ((t (:background "white"))) t)) Restart an xemacs, it will fail on startup: (1) (initialization/error) An error has occurred while loading /home/galibert/.xemacs/init.el: Assertion failed: (equal enabled-behavior-list val) Backtrace follows: signal(cl-assertion-failed ((equal enabled-behavior-list val))) (or (equal enabled-behavior-list val) (signal (quote cl-assertion-failed) (list ...))) (progn (or (equal enabled-behavior-list val) (signal ... ...)) nil) (assert (equal enabled-behavior-list val)) # bind (enable-list disable-list old-val) (let* ((old-val enabled-behavior-list) (disable-list ...) (enable-list ...)) (dolist (b disable-list) (disable-behavior b t)) (dolist (b enable-list) (enable-behavior b t)) (assert (equal enabled-behavior-list val))) (if within-behavior-enabling-disabling (set sym val) (let* (... ... ...) (dolist ... ...) (dolist ... ...) (assert ...))) # bind (val sym) (lambda (sym val) (if within-behavior-enabling-disabling (set sym val) (let* ... ... ... ...)))(enabled-behavior-list (resize-minibuffer recent-files mwheel jka-compr func-menu filladapt efs)) # bind (set comment requests now value symbol entry immediate args theme) custom-theme-set-variables(user (gutter-buffers-tab-visible-p t) (paren-mode (quote blink-paren) nil (paren)) (column-number-mode t) (enabled-behavior-list (quote (resize-minibuffer recent-files mwheel jka-compr func-menu filladapt efs))) (pending-delete-mode t nil (pending-del)) (toolbar-visible-p nil) (line-number-mode t) (user-mail-address &quot;galibert(a)pobox.com&quot;) (query-user-mail-address nil)) apply(custom-theme-set-variables user ((gutter-buffers-tab-visible-p t) (paren-mode (quote blink-paren) nil (paren)) (column-number-mode t) (enabled-behavior-list (quote ...)) (pending-delete-mode t nil (pending-del)) (toolbar-visible-p nil) (line-number-mode t) (user-mail-address &quot;galibert(a)pobox.com&quot;) (query-user-mail-address nil))) # bind (args) custom-set-variables((gutter-buffers-tab-visible-p t) (paren-mode (quote blink-paren) nil (paren)) (column-number-mode t) (enabled-behavior-list (quote (resize-minibuffer recent-files mwheel jka-compr func-menu filladapt efs))) (pending-delete-mode t nil (pending-del)) (toolbar-visible-p nil) (line-number-mode t) (user-mail-address &quot;galibert(a)pobox.com&quot;) (query-user-mail-address nil)) # bind (current-load-list) # (unwind-protect ...) # bind (load-file-name) # (unwind-protect ...) # (unwind-protect ...) # (unwind-protect ...) # (unwind-protect ...) # (unwind-protect ...) load-internal("/home/galibert/.xemacs/custom.el" t t t undecided) # bind (path handler filename nosuffix nomessage noerror file) load("/home/galibert/.xemacs/custom.el" t t t) load-user-init-file() #<compiled-function nil "...(10)" [init-file-had-error load-user-init-file-p load-user-init-file nil] 2>() # (unwind-protect ...) call-with-condition-handler(#<compiled-function (__load_init_file_arg__) "...(26)" [init-file-had-error user-init-file __load_init_file_arg__ errstr error-message-string message "Error in init file: %s" lwarn initialization error "An error has occurred while loading %s:\n\n%s\n\nBacktrace follows:\n\n%s\n\nTo ensure normal operation, you should investigate the cause of the error\nin your initialization file and remove it. Use the `-debug-init' option\nto XEmacs to enter the debugger when the error occurs and investigate the\nexact problem." backtrace-in-condition-handler-eliminating-handler t] 8> #<compiled-function nil "...(10)" [init-file-had-error load-user-init-file-p load-user-init-file nil] 2>) # (condition-case ... . ((error))) # bind (debug-on-error debug-on-error-from-init-file debug-on-error-should-be-set debug-on-error-initial) load-init-file() # bind (command-line-args-left) command-line() # (unwind-protect ...) normal-top-level() # (condition-case ... . error) # (catch top-level ...) To ensure normal operation, you should investigate the cause of the error in your initialization file and remove it. Use the `-debug-init' option to XEmacs to enter the debugger when the error occurs and investigate the exact problem. After the assertion failure, the status of enabled-behavior-list is: `enabled-behavior-list' is a variable declared in Lisp. -- loaded from "/home/galibert/xe/xemacs-21.5/lisp/behavior.elc" Value: (efs filladapt func-menu jka-compr mwheel recent-files resize-minibuffer) Documentation: List of currently enabled behaviors. Normally, don't set it directly; use `enable-behavior' or `disable-behavior'. OG.