# “yearmonthday” added to bibliography when using apa6 with biblatex and biber backend

I am trying to use the apa6 package with a more extensive version of this document:

\documentclass[man,a4paper, english]{apa6}
\usepackage{babel}

\usepackage{csquotes}
\usepackage[style=apa,sortcites=true,sorting=nyt,backend=biber]{biblatex}
\DeclareLanguageMapping{american}{american-apa}
\begin{filecontents}{ref.bib}
author = {Bradley, Margaret M and Cuthbert, Bruce N and Lang, Peter J},
title = {Startle reflex modification: Emotion or attention?},
journal = {Psychophysiology},
year = {1990},
month = {11},
day = {3},
volume = {27},
pages = {513--522},
number = {5},
publisher = {Wiley Online Library}
}
\end{filecontents}

\AtEveryBibitem{\clearfield{month}}
\AtEveryBibitem{\clearfield{day}}

\title{MWE}
\shorttitle{MWE}
\author{Me}
\affiliation{SO}

\begin{document}

\maketitle

Some more text before the bibliograpy and a citation \parencite{bradley1990startle} of course.

\printbibliography
\end{document}


However when compiling with latex I get this error:

! Undefined control sequence.
<argument> \mkbibdateapalongextra
{year}{month}{day}\iffieldundef {endyear}{...


When I continue compiling with biber main Biber this error pops up:

INFO - No sort tailoring available for locale 'nl_NL.UTF-8'


After the last compile with pdflatex I do get output, however some strange text appears in the bibliography:

Following the topic (Xelatex, Biblatex: biber.exe not working properly (IPC::Run) error) I have tried to compile with biber -f main, which didn't help either.

\AtEveryBibitem{\clearfield{month}}
\AtEveryBibitem{\clearfield{day}}


which didn't help either. I also tried filling out the day and month fields, but even if those are present the text (yearmonthday) still shows up in the bibliography. How do I get rid of that (yearmonthday) text in the bibliography? What does the error about the undefined control sequence \mkbibdataapalongextra mean?

All files including the complete log can be found here.

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The macro \mkbibdataapalongextra is defined in the language specific files american-apa.lbx, austrian-apa.lbx, etc., so if these are not loaded correctly then that macro is not defined, which leads to the issue you observed.

Be default, biblatex does not know to load american-apa, which is why you need \DeclareLanguageMapping{american}{american-apa}. However, it seems that you also need to tell babel to load american explicitly . I wrote "it seems" because I have not investigated in-depth, so I cannot say I fully understand the interdependence. However, the following code fixes your problem (I took the liberty of simplifying your MWE):

\documentclass{article}
\usepackage[english, american]{babel}

\usepackage{csquotes}

\usepackage[style=apa,sortcites=true,sorting=nyt,backend=biber]{biblatex}
\DeclareLanguageMapping{english}{american-apa}

\begin{filecontents}{ref.bib}
author = {Bradley, Margaret M and Cuthbert, Bruce N and Lang, Peter J},
title = {Startle reflex modification: Emotion or attention?},
journal = {Psychophysiology},
year = {1990},
month = {11},
day = {3},
volume = {27},
pages = {513--522},
number = {5},
publisher = {Wiley Online Library}
}
\end{filecontents}

\begin{document}

Some more text before the bibliograpy and a citation \parencite{bradley1990startle} of course.

\printbibliography

\end{document}

-