I recently started using standalone to compile a tikzpicture and convert it to PNG. Thus I use the following type of Document together with
\documentclass[convert,tikz]{standalone}
\usepackage[ngerman]{babel}
\begin{document}
\tikz\node {Hallo da drau"sen};
\end{document}
and get the error message
(C:\Users\...path..\Test.aux
! Package babel Error: You haven't loaded the option ngerman yet.
See the babel package documentation for explanation.
Type H <return> for immediate help.
...
l.3 \select@language{ngerman}
You may proceed, but expect unexpected results
)
Neverless the result indicates that the ngerman additions by babel were loaded (i.e. the ß for "s is being typeset correctly).
I am aware of this question which proposes deleting all auxiliary files. But on the next run the error is back.
Further investigation shows the possibility to condense the problem even more:
\documentclass[convert]{standalone}
\usepackage[ngerman]{babel}
\begin{document}
X
\end{document}
The error however does not occur without the convert option or without babel. The choice of language doesn't seem to make any difference.
standalone. – egreg Aug 31 '15 at 14:15