How can I make the Galaxy S3 detect media on my sdcard? I have transferred some mp3s onto my sdcard using samba but the operating system doesn't seem to automatically detect them as it would if you copied it using MTP or whatever.  How can I force it to detect them?
My S4 wouldn't recognize music on my external SD-card. You can fix this on your S3 by going to settings> more > storage > remove SD-card. Wait till it says 'You can now safely remove your SD-Card' then remove the card out your phone. Clean your RAM and then put it back in again. Wait a few seconds till it's succesfully installed and your card will be visible. I.E for music open your music player and it'll all be there. Make sure the files aren't in too many subfolders or your phone will not find it and show it in your music player.

Have a nice day,