src/Doc/Sledgehammer/document/root.tex

--- a/src/Doc/Sledgehammer/document/root.tex	Thu Oct 17 18:53:00 2013 +0200
+++ b/src/Doc/Sledgehammer/document/root.tex	Thu Oct 17 20:03:37 2013 +0200
@@ -1038,6 +1038,8 @@
 simultaneously. The files are identified by the prefixes \texttt{prob\_} and
 \texttt{mash\_}; you may safely remove them after Sledgehammer has run.
 
+\textbf{Warning:} This option is not thread-safe. Use at your own risks.
+
 \nopagebreak
 {\small See also \textit{debug} (\S\ref{output-format}).}
 \end{enum}