My daughter has an old Rio Cali (the 128MB version) with an additional 256MB SD expansion card. When the player is connected to the computer and being read by Rio Music Manager, it shows the entire capacity as available and even allows it all to be filled with music. The problem is that more often than not, the player decides to ignore the additional card, only displaying the songs that are written to the internal memory. At other times, however, the full list is available.

Has anyone else had this problem, and what might be the cause and solution?

EDIT: I forgot to add that the player is running firmware v. 2.43.