I have used quite some time searching for a solution to my compile problem. The document worked fine untill yesterday. After adding some new references, compiling stoped working properly. I have however used latex only for a few months, so the error might be an easy fix.

My error code in the blg file is:

[836] Utils.pm:209> ERROR - BibTeX subsystem: 
line 1375, syntax error: found ",", expected one of: number, name (entry 
type, key, field, or macro name), end of entry ("}" or ")") or quoted string 
({...} or "..."). 

I have biber 2.11 and miktex 2.9 and thought it could have been the cache file as suggested in a previous thread with 2.11 versions, but it did not do the trick to delete that either.


This is how my "main" document looks like:



% Math syntax 

% Figures

% Biblography and citing

% Frontpage


% Frontpage     

% Abstract

% Table of contents

% Document

% References                        

  • The error message is the best lead you have. Check out line 1375 or thereabouts in your .bib file (don't open it with JabRef, open it with a normal text editor) and check if all comas, quotation marks and braces are where they are supposed to be. You can try to isolate the issue by deleting a few entries and checking if the error persists. Keep in mind that the error message might be indicating a point slightly after the real error occurred, sometimes the symptoms follow the cause by a few lines. – moewe Oct 31 '18 at 9:06
  • As far as I can tell from the error message this should not be cache issue and it should not be a permissions thing. At the moment it just looks like something is missing in the .bib file. Do check if the entry in question has a key: An empty key would cause such a message and is one of the few things that could be messed up in an automatically generated bibliography file. – moewe Oct 31 '18 at 9:08
  • Thank you so much. You were right, it was a missing bibkey. – Andreas Grøvan Aspaas Oct 31 '18 at 9:42

Such an error can be produced with entries that lack an entrykey.

Biber will throw an error of the form

syntax error: found ",", expected one of: number, name (entry  type, key, field,
              or macro name), end of entry ("}" or ")") or quoted string 

if you leave the key empty. Unfortunately, this error is so serious that Biber will not try to process the (rest of the) file properly. That means that one entry without a key can render your entire .bib file unusable.

In cases like this you should also get a warning similar to

WARN - Invalid or undefined BibTeX entry key in file 'C:\Users\<User>\AppData\Local\Temp\bGm7haxaPA\skjshjshs.bib_16176.utf8', skipping ...

There are technical reasons for the slightly unusual order of these messages, see https://github.com/plk/biblatex/issues/818.

BibTeX is slightly more forgiving and allows you one empty entry key (you can't have two entries with empty keys, after all the key must be unique). But entries with empty keys can't be cited and with biblatex don't make it to the bibliography even with \nocite{*}

So I strongly advise that all entries in your .bib file have a non-empty, valid entry key.

Because I think it makes sense to warn users not to leave the key empty, I opened an issue for JabRef at https://github.com/JabRef/jabref/issues/4440.

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