Why is the list of recent files in Prism's File menu empty?

Prism lists recently opened or saved files in its File menu. Prism Windows simply lists these at the bottom of the menu. Prism Mac has a "Recent Files" command that leads to a secondary menu of recently used files. 

Problem 1 (Mac only) You've told OS X to not show recent files

The number of items showing in the recent files menu is set in the Appearance or General (depending on OSX version) pane of the Mac Preferences dialog (note this is the overall Mac/OSX preferences dialog, not Prism's preference dialog). If you set this dialog to "none", then Prism's list of recent files will be empty and show the meaningless phrase "Clear menu". This can also happen when you update OS X.

To fix the problem, choose the number of files you want to see (we suggest 15), then close the preferences dialog and restart the computer to populate and display the recently opened files list within the Prism application itself. 

Problem 2 (Windows or Mac). The Prism preferences file got damaged or deleted. 

Prism stores the list of recent files in its preference file. If that file gets damaged or deleted, Prism will not remember the list of recent files. 

But note that even if the recent file list is empty, the files are not gone. They are still saved wherever you saved them (unless you deleted, renamed or moved them).  You just need to find the appropriate folder, and open the files. Or use Windows search or Mac Spotlight to search for your files.