emacs latex auctex error: void-variable latex-mode

Question

I have upgraded to Fedora 20 and suddenly latex-mode/auctex is broken. I receive an error whenever trying to go into latex mode:

command-execute: Symbol's value as variable is void: latex-mode

Using toggle-debug-on-error I see:

Debugger entered--Lisp error: (void-variable latex-mode)
  byte-code("\301\302\303\304\305\306\307\310\307\311&  \210\312\313\303\314\315\316\307\302&\210\312\317\303\320\315\316\307\302&\210\312\321\303\322\315\316\307\302&\210\312\323\324\325\315\316\307\302&\210\312\326\303\327\315\330\307\310&\210\331!\210\332\333\334\"\207" [latex-mode custom-declare-group LaTeX-macro nil "Special support for LaTeX macros in AUCTeX." :prefix "TeX-" :group LaTeX TeX-macro custom-declare-variable TeX-arg-cite-note-p "*If non-nil, ask for optional note in citations." :type boolean TeX-arg-footnote-number-p "*If non-nil, ask for optional number in footnotes." TeX-arg-item-label-p "*If non-nil, always ask for optional label in items.\nOtherwise, only ask in description environments." TeX-arg-right-insert-p t "*If non-nil, always insert automatically the corresponding \\right.\nThis happens when \\left is inserted." LaTeX-mode-hook "A hook run in LaTeX mode buffers." hook TeX-abbrev-mode-setup add-to-list auto-mode-alist ("\\.drv\\'" . latex-mode)] 10)
  command-execute(latex-mode record)
  execute-extended-command(nil "latex-mode")
  call-interactively(execute-extended-command nil nil)

Help please!What broke my LaTeX mode and how can I fix it?

Running GNU Emacs 24.3.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.9.10) of 2013-08-14 on buildvm-17.phx2.fedoraproject.org

Answer 1

Following https://github.com/bbatsov/prelude/issues/407 I re-installed AucTex. That seems to have done the trick. I used list-packages and then deleted AuxTex then reinstalled. I can now use LaTeX mode.