Rio pearl directory corrupted
first, and this is always good: If available, firmware for the Rio Carbon can be downloaded online.
Second, this might be the problem:
The Rio Carbon communicates with your computer differently in MTP mode than it does in MSC mode. When in MTP mode, the Rio Carbon cannot display hidden files in folders, cannot allow transfers to the root Rio Carbon directory, and cannot allow the creation of new folders. (Folders can be transferred to the Rio Carbon using drag-and-drop and copy-and-paste methods.) To use traditional folder options, change the Transfer Mode settings to put the Rio
Carbon in MSC mode.
"..Removing the Rio Carbon from a USB connection before Idle is displayed on the screen may result in a corrupting the player's file system.
If for any reason you suspect that your Rio player's file system has been corrupted, reformatting the player will restore the file system to its original state..."