Is it only video files that are saved twice? How about music files?

You shouldn't be seeing shortcuts in your saved or shared folders... should be the whole file. Are you looking in your saved & shared folders within LW's library?

If that's where you're looking, then you're not actually seeing 2 copies of the same file - you're just seeing a file that's saved to your computer which appears in 2 places in LW's library. LW's library doesn't actually contain any files - it just reflects what you have in LW's saved, shared & incomplete folders... eg if you've chosen to share your saved folder then whatever's in the folder that LW saves to on your HDD will show up in LW's library when you click on Saved Files & also when you click on Shared Files.

Go to LW's library, click on Shared files... highlight a movie file & click Explore. Now your shared folder will open outside of LW. Are the files saved twice within that shared folder?