Rename command doesn't show file extension sometimes

I'm having difficulty with the .xxx file extension not always showing with a simple rename rule. Most of the time it works perfectly, except when a file is processed that does not have the extension showing in the original name. In this instance I can't seem to get the extension to show up in the renamed file either.

I'm working mostly with .pdf files with a simple rule like the following:

<date added> Sales Order<extension>

Although the Mac doesn't have difficulty knowing what type of file it is dealing with even if the extension is not appended to the name, I would like to include the .pdf extension in the name to avoid problems if the files are later used on a PC.

It seems like there should be a simple answer that I'm just missing.

Select the file in Finder and do "Get Info". It may be the case that the "Hide Extension" checkbox is checked. This hides the extension, but only in the user interface. The file still has the extension and will still have it if you transfer or access the file from a Windows machine. It's just a display issue.

Thanks for the reply.

Yes, that box in the Get Info window is checked for the problem files.

Is it possible to "uncheck" that box with a rule or a script? If so, any suggestions?

Thanks for your help.

go to finder preferences (open finder, cmd+, is the keyboard shortcut). Switch to the advanced tab, and make sure that the checkbox 'show all filenames extensions' is checked. That should solve your problem. Like Mr_Noodle said, that is just a visual indicator in the finder. Only the get info method or dragging the file to some text editing software will show you the real extension for sure. (Personally I don't like seeing extensions so I remove them all, prevents having files with long names appear with dots in the middle of the name which I absolutely hate).

Thanks for the help guys -- problem solved!