empty bibliography

Question

My preamble

\documentclass[12pt,a4paper]{report}
\usepackage[utf8]{inputenc}

\usepackage[english,greek]{babel}
%\usepackage[square, numbers, comma, sort&compress]{natbib}  % Use the "Natbib" style for the references in the Bibliography
\usepackage{verbatim}  % Needed for the "comment" environment to make LaTeX comments
\usepackage{biblatex}
\usepackage{amsmath,amsfonts,amssymb,amscd,mathrsfs,enumerate}
\usepackage{amsthm}
\usepackage{tikz}
\usetikzlibrary{matrix}
\usepackage[all]{xy}
\usepackage{relsize}
\usepackage{pifont}
\usepackage{mathtools}
\usepackage[all]{xy}
\usepackage{relsize}
%\usepackage{fourier}
\usepackage{esvect}
\usepackage{csquotes}
\usepackage{substitutefont}
\usepackage{graphicx}
\substitutefont{LGR}{\rmdefault}{artemisia}
\usepackage{pgf,tikz}
\usepackage{mathrsfs}
\usepackage{adjustbox}
\usepackage[capposition=top]{floatrow}
\renewcommand{\qedsymbol}{\textcolor{black}{$\blacksquare$}}
\allowdisplaybreaks
\usepackage{thmtools}

\useshorthands{;}
\defineshorthand{;}{?}


\usepackage{biblatex}
\addbibresource{bibl.bib}

then before the \end{document} I wrote

\nocite{*}
\printbibliography

but nothing appears (the bibliography does not appear) and I get an error "empty bibliography on imput line 616".

Any help?

Maybe this helps

[0] Config.pm:304> INFO - This is Biber 2.12
[0] Config.pm:307> INFO - Logfile is 'output.blg'
[43] biber:315> INFO - === Sat Oct 19, 2019, 07:04:29
[75] Biber.pm:371> INFO - Reading 'output.bcf'
[180] Biber.pm:886> INFO - Using all citekeys in bib section 0
[204] Biber.pm:4093> INFO - Processing section 0
[217] Biber.pm:4254> INFO - Looking for bibtex format file 'bibl.bib' for section 0
[219] bibtex.pm:1523> INFO - LaTeX decoding ...
[229] bibtex.pm:1340> INFO - Found BibTeX data source 'bibl.bib'
[255] bibtex.pm:94> FATAL - Caught signal: SEGV
Likely your .bib has a very bad entry which causes libbtparse to crash: Operation not permitted

Answer 1

I have same problem (via Overleaf). As a background, I migrated my bibliography from natbib to biblatex with the reference items over 300. As far as I understand, biblatex in Overleaf uses biber as a default?

Then I tried to use bibtex as its backend

\usepackage**[backend=bibtex]**{biblatex}, and magically it works!

Hope this helps.