I have a brand new Samsung 128GB EVO Micro SDXC for use with my Note 4. I did get it from eBay, but it came in actual Samsung packaging and looks legit. If it's a fake, they did a hell of a job. I formatted it on my Mac in good ol' FAT 32 and copied about 70 gig of music over with a USB adapter, then reinstalled in my phone. Using DoubleTwist, suddenly I only had folders in the 0 - C title range, all else has been deleted. Also, certain mp3 tracks within those retained music folders wouldn't show as playable, the "unknown file format error" yet all of these files are good ol' mp3 files..When viewing the files in Android File Transer, they look just fine. Coping them BACK from the card to my Mac, they're unplayable, and VLC says they're "undf", so perhaps corrupt.
So I get frustrated and reload the missing D - Z files (several hour copy processe), reload my phone and use the generic "music" player by Samsung. Now I've got 0 - D folders, nothing else! I've also tried VLC (won't load!) and PowerAmp, these 'unknown' mp3 are still unplayable. I don't see how the card is bad, as it was brand new in the OEM packaging. Should I just reformat again and try again? Just so strange how it retains some folders in alphabetical order then gives up on down the list...? Thank you, Aaron