Hi,

before I forget, I have been thinking about this a lot. It may look
tangetial but IMHO it is not...

One thing is having
```
(setq org-cite-export-processors '((beamer . biblatex)
                                (latex .  biblatex)))
```
in your emacs configuration (because you need it for most situations)
and another thing is that this options forces the export process to
check that you are using a bibliography in each and every document you
generate. I may want to write a quick document  with org-mode and
generate a PDF with the LaTEX backend and another thing is that I will
need to include a bibliography even if I don't need it.

Currently, with that config for ox-latex, this MWE chokes because
their is no reference to a bibliography:

------ mwe.org -------------
#+LATEX_CLASS: letter
#+DATE: 01-Mar-2023

Dear friends!

It sucks a bit to need a bibliography to export this letter!

Best, /PA
-----------------------------------
This is the minimal emacs config that chokes at PDF export (C-c C-e lo)
----- mwe.el -----------------
(require 'org)
(require 'ox-latex)
(setq org-cite-export-processors '((beamer . biblatex)
                               (latex .  biblatex)))
(setq org-latex-pdf-process
      '("latexmk -pdflatex='pdflatex --shell-escape
--interaction=nonstopmode' -pdf -f %f"))
(add-to-list 'org-latex-classes
             '("letter"
               "\\documentclass[a4paper]{letter}"))
-------------------------------

To try:

emacs -Q -l mwe.el mwe.org

and then C-c C-e l o in Emacs to get the attached error message and no PDF.

This is all on

GNU Emacs 30.0.50
Development version fad366506974 on master branch; build date 2023-02-23.

It would be nice to take this discussion as an opportunity to 'fix' this

Best, /PA

-- 
Fragen sind nicht da um beantwortet zu werden,
Fragen sind da um gestellt zu werden
Georg Kreisler

Headaches with a Juju log:
unit-basic-16: 09:17:36 WARNING juju.worker.uniter.operation we should
run a leader-deposed hook here, but we can't yet