Sample transfer problems

I have been using the 16GB card that comes with the OT and having no problems. Its started to get crowded so i thought I would switch to my 64GB one that I bought a while ago.

I started by copying my old stuff to the computer, after that I tried to copy it to my new card. (formated it in the octatrack).

After copying the stuff to my new card, I could only find a new folders so I went back into USB mode and not everything was there. So i Formated again and this time only moved a few folders. It went slower this time to transfer seeing as i only copied a small part. But it worked.

I proceeded to copy folders one by one until i copied one folder that went a lot faster than the others and that folder contained transparent audio files (OS X) that were unplayable.

It seems after a few gigabytes it starts copying real fast and not doing a good job at it.

Any clues?

edit: Im using the exact same card model that came with the octatrack, only the 64GB version, Kingston Ultimate 266X.

edit2: also, if i browse to a folder containing these “corrupt” files, the folder is also transparent and after that its impossible to eject the OT because it says its “in use”.

update: tried under windows.
I thought it went well there for a while until i started to browse through all the samples and saw that they too were corrupted. Sample names appeared as random symbols.

Ok so now I can’t even format the card, tried on windows 8 , rebooting to ms-dos prompt, osx. Bought a card reader, tried another card reader at work. Tried to delete partitions, tried full format (1% in like 24 hours, cancelled that one…). Nothing.