How long did you wait? It can only appear to be frozen (the progress bar doesn’t really scale correctly to the time it will take to finish). Things that can cause it to take a long time: a large number of files and/or folders, corrupted files, and sloppyID3 tags.
More about tags: when it says “refreshing your media”, what it’s really doing is building a database of all the information in the tags (title, artist, album, track number, etc.). The player can choke on messy tags, particularly very long comments. For some reason, some people try to put the artist’s entire history (or some other ridiculously verbose nonsense) in the “Comment” tag. The best thing to do is to use a progam like MP3Tag (highly recommended, and FREE) to clean up the tags, deleting comments and paring down the other tags to only the essentials. Whatever tag editor you use, change the settings to save tags in ID3 v2.3 ISO 8859-1 format if possible. This format is the most compatible with Sansas.
If your tags are clean and it still freezes up, you probably have a corrupt file. To make it simpler to isolate the problem file(s), format the player (from the Settings>System Settings menu) and start reloading your files in smaller batches until it freezes up again.
