# ! Illegal parameter number in definition of \NewValue

Everything works fine until I added the following URL reference to my references.bib file. The URL reference is output but I am getting the error

Illegal parameter number in definition of \NewValue.

@misc{jdk,
author = {Oracle},
title = {Platform, Standard Edition 7
Development Kit},
note = {Accessed: 2015}
}


MWE:

\documentclass{article}
\usepackage[backend=bibtex]{biblatex}
%\bibliography{references}
\begin{document}
Hallo world\cite{einstein} I do not if it \cite{jdk} Tree Tree bla bla will work test \nocite{Doe:2009:Online}
\printbibliography
\end{document}

• Without a minimal working example (MWE) it's impossible to say anything. – egreg Jan 30 '15 at 21:20
• I have deleted the part from my refernces.bib and everything works again if I add it then I am getting the error! I think it is up to the jdk reference – ocean Jan 30 '15 at 21:22
• Have you added \usepackage{url}? – user11232 Jan 30 '15 at 22:41
• Following up on @HarishKumar's suggestion: after adding the instruction \usepackage{url}, did you rerun latex, bibtex, and latex twice more? – Mico Jan 30 '15 at 23:22
• @HarishKumar biblatex already loads url. – egreg Jan 31 '15 at 10:46

You should use the url and urldate, rather than howpublished and note:

\begin{filecontents*}{\jobname.bib}
@misc{jdk,
author = {Oracle},
title = {Platform, Standard Edition 7 Development Kit},
urldate = {2015},
}
\end{filecontents*}

\documentclass{article}

\usepackage[backend=bibtex]{biblatex}

\DefineBibliographyStrings{english}{%
urlseen={Accessed:}% %%% not visited on'
}


Note that the filecontents*` environment is just to make the example self contained and you can use your file (after modifying it as suggested).