Hi friends ! I have bought an 512 MB mp3 player ( Chinese - Sony duplicate ). In the player, it showed 497 MB space n in PC also the same was shown. But when i was transferring songs, it could not take beyond 240 MB although the rest space was being shown free by windows and the player also. Windows gave error message that *.mp3 is not a valid file or something like that. I tried several times and tried even other files other than mp3 but it was futile. Then I found an interesting thing , when i deleted some of the mp3 files from player n added other mp3 files , its capacity decreased more . Now it holds 220 MB files (as compared to earlier 240 MB). When i tried to fix the file system errors (F:\ Right Click > properties > Tools > Error Check ) Now the windows n player both show that around 495 MB space is occupied ,although total size of mp3 files in player is just 220 MB. What is happening ? I don't dare to format it bcoz one of my friend spoiled his pen drive trying formatting it and may be the player has some mp3 driver n system files which may be lost.