I am new LaTeX user (with Overleaf)

I have this kind of error and I have no idea how to fix it. My hypothesis is that I delete something in bibliography section, and now I don't know how to continue.

the error is

Undefined control sequence.
l.43 \abx@aux@page
(no line number):
This is BibTeX, Version 0.99d (TeX Live 2015/Debian)
Capacity: max_strings=35307, hash_size=35307, hash_prime=30011
The top-level auxiliary file: 0-complete.aux
The style file: biblatex.bst 

and the part related the code is:



someone can help me please?

  • I have had similar errors a few weeks ago. Is it possible that you work on several machines on your files, which have different biblatex/biber versions? Or have new biblatex but old biber? Aug 17, 2016 at 14:53
  • yes I work with different PCs. how can I fix it?
    – Lucia
    Aug 17, 2016 at 21:31
  • Make sure to have the same installation level on all machines, e.g. TeX Live 2016 with online updates. Aug 17, 2016 at 22:23

1 Answer 1


This is most likely caused by an outdated .aux file when you changed the bibliography style, or switched from biblatex to bibtex. You can try clearing the intermediate files on Overleaf, by clicking on the "recompile from scratch" option at the bottom of the error message window, and see if that clears the errors.

(See updated instructions for Overleaf v2 here: https://tex.stackexchange.com/a/303808/226)

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