>>> "UB" == Uwe Brauer <oub@mat.ucm.es> writes:

> Hi

> I am running emacs 29 and org mode 9.6.9

> I have set (setq org-latex-line-break-safe "\\\\")

> Nevertheless the following example 

This helped


(defun my-latex-insert-hline-always (row backend info)
  "Add a hline to every row when exporting to  LaTeX."
  (when (org-export-derived-backend-p backend 'latex)
    (replace-regexp-in-string "\\\\\\\\\\[0pt\\]\\|\\\\\\\\" "\\\\\\\\ \\\\hline" row)))

(add-to-list 'org-export-filter-table-row-functions 'my-latex-insert-hline-always)