Thanks to all who answered. The problem was that I have a cron job
that continuously update my packages including LyX in the
background. Once I hit reconfigure, everything was okay.
--
myriam
>
> You shouldn't here, either. Assuming that you have a document loaded,
> File -> Export should be populated automatically with all formats for
> which LyX has a conversion path. Are you saying that it's not? If
> not, can you View -> DVI or View -> PDF (pdflatex)? (If the answer is
> not to that as well, either the configuration script burped or
> something's up with your LaTeX distribution. Or neither of the above.)
>
> /Paul
