# Not in outer par mode

For example:

*\mbox{\marginpar{foo}}

! LaTeX Error: Not in outer par mode.

The error comes when you try to build something movable inside a box. Movable things, in this context, are floating environments (figure and table, for example), and \marginpars. LaTeX simply doesn’t have the mechanisms for floating out of boxes. In fact, floats and \marginpars themselves are built out of boxes, so that they can’t be nested.

If your error arises from \marginpar, you simply have to think of an alternative way of placing the command; there is no slick solution.

If a floating environment is the culprit, it may be possible to use the “H” placement option, provided (for example) by the float package:

\parbox{25cm}{%
\begin{figure}[H]
...
\caption{Apparently floating...}
\end{figure}%
}

This example makes little sense as it stands; however, it is conceivable that sane uses could be found (for example, using a package such as algorithm2e to place two algorithms side-by-side).
algorithm2e.sty
algorithm2e
float.sty
float