All the versions of the CDJ-2000, CDJ-900 and CDJ-850 supports the following USB formats:
Most DJs use and recommend FAT32, but is it the best format?
FAT16 is the ancestor of FAT32, has more limitation and no advantage.
FAT32 is the most used version of the FAT file system conceived by Microsoft. Its main advantage is its great compatibility with most products: televisions, multimedia boxes, the Playstation 4 all use the Fat32. It is also compatible for writing and reading on both Windows and Mac computers. Its biggest flaw is the size limit for each file of 4 GB maximum (and the limit to a total disk capacity of 2 TB). This limit doesn’t really matter in our case as their is no music files that big.
HFS+ also called “MAC OS Extended” is the basic format used on a Mac computer. It doesn’t have the size limitation of the FAT32 but its biggest flaw is not being compatible with the Windows environment.
If you have a MAC and will not be sharing files with a PC, HFS+ will be faster and should be your format of choice. In all other cases you should go with FAT32.