You probably have the files stored on a secured partition. To access it, you'll need Lexar's software installed.http://www.lexar.com/support/jumpdrive-secure-faqs
These secured partitions should only really be used for files which are private in nature. Their purpose is to protect you if you should lose the drive - whoever finds it can't read your files without your password. But for mundane stuff like music files, you can just store them on a regular unsecured partition. Then you won't have to install special software to access them.