Okay, So I have the samsung galaxy s4, a 64gb samsung sd card and a macbook pro. I have had problems with putting music onto the sd card. I do not have the capacity to use wifi syncing as I am on a limited data usage. I have around 25gb of mp3's and m4a's to put onto the card. I have tried the following: 1. isyncr - does it well for a while but then comes up with error messages 2. android file transfer - successfully transfers files however the recurring problem is that when i go on my phone, some songs are able to play whilst other are 'unsupported' or 'cannot be played'. 3. keis doesn't work 4. I have plugged the sd card in an adaptor straight into my mac, formatted it from there and put the music on, but when i put it in the phone it says 'damaged sd card' - therefore the way in which the macbook formats isn't compatible so I have formatted from the phone instead from thereon. I have tried doing 25gb in smaller batched, works for around 2 batches then problems occur with 'unsupported' and 'cannot be played'. I have located these songs in the sd card in the phones menu options, they do not play. I have tried this with google music, rocket player, the stock samsung player and meridian. I have started the phone again and used media scanner to no avail. When restarting the phone, in one instance I transferred around 1000 songs, only 193 remained when i turned to phone back on. Using google music cloud service is not an option as I want these songs on my phone and I dont have the data to use it. What do i do? Please help.