MP3 Files Not Copied Correctly

I have a new SanDisk 64GB Ultra microSDSC SD class 10 TF card; formatted FAT32.

I have about 400 MP3 files I want to copy from my hard drive (NTFS) to the card (FAT32), to be used in an MP3 player. After I copy a group of files, sometimes some of the files on the card do not show the length values, so I recopy them. Usually, but not always, this works.

When the first set appears OK, I then go to the next set, and so on.

For some reason, a file that appeared OK, after other files have been copied, will not show the length field.

All of these files correctly show the length in Windows Explorer for the hard drive, but for some reason this gets lost in the copied version; even though the copied version shows the name, type, date, and size.

Anyone have any idea what's causing this and how to correct?

Thanks for any info.

Thanks for your note. It seems that no one else has had this issue.

I've used several copy methods (within Windows Explorer, xcopy in a batch file, Syncback).

I haven't had this issue with my other SD card or with two different flash drives. I have reformatted this SD card a couple times, once to FAT32, once to exFAT. In both formats, the problem occurs.

I filed a replacement request with SanDisk today, since I strongly believe the card is defective. Hopefully, they'll approve it and send me a new card that won't exhibit the problem.