Problem with SD Card and music?

[Marina L]

Okay so I just bought my Samsung Galaxy S3 in January along with a SanDisk Ultra 64 GB MicroSDXC Class 10. I have a lot of music files (around 9 GB) so I put them in the external SD drive. I think I first tried putting my music in it using my Mac and I had some trouble at first putting it in with DoubleTwist with my PC. But in the end I got my music in perfectly but then whenever my music would be playing, it would sometimes say (Sorry the music player cannot support this audio file) and it would rapidly switch to the next song to the next. I lurked around other forums and they say to reset the phone or reformat the card. Well I did both and my music played perfectly when I let my phone format it a few days ago but today I tried playing it again and the message came up again. I tried restarting my phone, unmounting/mounting my sd card but nothing would work and for some reason my song titles got messed up in the progress. So I had to reformat my card again and put my music back on AGAIN. There obviously has to be a problem somewhere. I can't keep having to restart my phone like that all the time or reformat my stuff. I know my music files aren't corrupted because I tried putting them in the internal SD (although it cramped the space up something awful) and it played them without any problem. Suggestions?