How to avoid overwrite existing files


Fisrt of all, sorry for my "stupid" question. Surely the answer exists in this forum but I've unable to find it.

After installed this application (wich I only will use to transform documents "doc" to "pdf") I have experienced a very small problem. Imagine that you make a mistake and convert to PDF a document wich name already exists. By my experience when it happens, a warning message appears in order to avoid overwrite existing files.

How could I configure the options to get this alert???

Thanks in advance,

CAT71, from Catalonia