I have a llncs document (Springer Lecture Notes in Computer Science) which requires a bibliography style splncs04. However, I get the error message "Style 'splncs04' not found". I have read and tried to implement these questions

LaTeX can't find my .bst file. How do I show it the way?

and

Where do I put .bst files

but although I tried putting the bst file both in the tex file folder and in ~/Library/texmf/bibtex/bst it gave the same message. Here is my MWE (tex document)

\usepackage[backend=bibtex, style=splncs04]{biblatex}

\begin{document}

~\cite{TarskiGeometryAFP}

\printbibliography

\end{document}

and bib file

@article{Tarskis_Geometry-AFP,
author  = {T. J. M. Makarios},
title   = {The independence of Tarski's Euclidean axiom},
journal = {Archive of Formal Proofs},
month   = oct,
year    = 2012,
note    = {Formal proof development: \url{http://isa-
afp.org/entries/Tarskis_Geometry.shtml}. Thesis:
\url{http://hdl.handle.net/10063/2315}},
ISSN    = {2150-914x},
}
• You are loading biblatex. biblatex has its own format for bibliography styles and is not compatible with the .bst files used by classical BibTeX. See tex.stackexchange.com/q/25701/35864 for a bit of background on what biblatex is. If you want to use a .bst file you must drop biblatex and return to the BibTeX way of creating bibliographies. Basically follow tex.stackexchange.com/q/5091/35864 in reverse. – moewe May 17 '18 at 18:24

You are loading the biblatex package. biblatex is a reimplementation of the BibTeX bibliography system and uses its own system to style the bibliography and citations. In particular does not use .bst files to control the output of citations and the bibliography. That means that you can't use .bst files with biblatex. See also Biblatex induced headache: Bibliography bst style not found.

If you want to use splncs04.bst you must go back to the BibTeX way of creating bibliographies. You'll essentially have to follow What to do to switch to biblatex? in reverse:

• Drop \usepackage[...]{biblatex}.
• Replace \addbibresource{<bibfile>.bib} with \bibliography{<bibfile>} and move it to where \printbibliography is. (\bibliography{<bibfile>} will print the bibliography list.)
• Remove \printbibliography.
• Add \bibliographystyle{<BibTeX style>} to your document. (It doesn't matter where you put that line as long as there is only one \bibliographystyle in your document. Often people put it next to the \bibliography to keep both bibliography commands together, but one might feel that \bibliographystyle is more appropriate in the preamble.)
• With biblatex you probably used Biber as backend and you may have configured your editor to run Biber instead of BibTeX. You will have to make sure to run BibTeX. Essentially you need to follow Biblatex with Biber: Configuring my editor to avoid undefined citations in reverse.
• One last note: It is a good idea to delete all temporary files (.aux, .bbl, .bcf) after your switch back to BibTeX. Some biblatex commands may remain in those files and could cause issues on the next run. The files are recreated on a full LaTeX, BibTeX, LaTeX, LaTeX run, so deleting them is safe.

you'd end up with something looking like