Hello Uwe, On 29/12/2025, Uwe Brauer wrote: > However if TeX-output-dir is set to "build" > > Then the backend=biber works, but backend=bibtex gives the following error > when running bibtex Yes, indeed.
The fix is easy: just add the output directory to BIBINPUTS and TEXINPUTS. For example BIBINPUTS=build:. TEXINPUTS=build:. There might be an argument to having this done automatically in AUCTeX (for all commands or just for BibTeX) but I am not sure if there are other consequences. latexmk does this by default so I don't run into this issue. -- Al
