when I went to check what's going on, I found out many of the folders were been replaced by empty folders that their name starts with the letter "µ".
like for example, the folder "ACDC" became "µCDC".
I tried transferring everything back again facing the same problems with different folders.
I tried doing a factory reset and tried moving the song to the SD card through a card reader, and checked the files were OK before inserting the SD card back into the device and they seemed fined, but after I inserted the SD card I noticed the folders got curropted again.
also before I inserted the SD card there was like 500 MB of free space on the SD card, while after I inserted it suddenly the was like 15 GB of free space, caused by so many data that got deleted.
I don't believe the SD card is damaged, but that my device is messing my things up....
I also remember that I couldn't transfer any video files to the SD Card when it was in the device and could only transfer them into the device's internal memory.
what can I do?