Error “All of the media was imported...” pops up when I try to import files in to CyberLink MediaShow. Why?

When you import a media file in CyberLink MediaShow and you get the following message:

CyberLink MediaShow 4 and above version keeps track of all the video/photo files you’ve ever imported. The problem may be that you previously imported these files into CyberLink MediaShow.

To display the imported media file, try disabling [Exclude duplicates].