I have an old (Maxtor One Touch) 300G drive that years ago I used for backing up files from a Windows PC. It's NTFS.
On my (MacBook Pro, Retina, 15-inch, Late 2013, Yosemite 10.10.2) system I can easily access it as USB, and copy over all of the files - except one folder.
Almost 20K files with over 80G of content copy over fine. Except this one directory. There seems to be nothing special about that directory - 112 files, 63 MB worth, all with the expected "You can only read" access rights since it's NTFS. But not a single file in that directory can be copied. I can list the files, but can't read them.