Find Your iTunes Playlist
If you cannot find your iTunes playlist, the first thing to do is search your computer for the files.
In Windows XP, click Start and then click Search. Click on All Files and Folders. Type the file extension of your playlist files into the All or Part of the File Name box and click Search.
In Windows Vista or Windows 7, click Start and type the file extension into the Search box.
In Mac OS X, go to File in the Finder and select Find. Type the file extension of your playlist files as the search term and click Search.
Your iTunes file extensions may be .m4p, .m4v, .m4b, .mp4, .m4r, .m4a, .ipa, ipg, .ite, .itlp or .epub
Finally, check your Recycle Bin in case they were accidentally deleted. If you are unable to get back your iTunes playlist this way, proceed to the next method.