abort: untracked files in working directory differ from files in requested revision

[Uwe Brauer]

Hi 

I know I should not add bin files, such as pdf, but for some reason I
have to do so.

So 

hg status does not return anything 

But 

hg up 585
build/master-english.pdf: untracked file differs
abort: untracked files in working directory differ from files in requested revision


That seems to me a funny error, any idea what to do?