Cannot format My Book 1230 Media to MS-DOS

A new 6TB My Book connect to Mac system OS X Yosemite 10.10.5, Some how at Disk Utilities cannot be erase/format to MS-DOS, the menu under “Format” do not show the option of MS-DOS, only show Mac Ox Extended and ExFat. And weird things is I can partition the drive to 2 MS-DOS format partition. Need help, how to make the device become MS-DOS format?


FAT32 (called MS-DOS (FAT) in Disk Utility) is a cross compatible file format although you will be limited to 4GB maximum per single file. So, that’s why it allows you to create 2 partitions and not one.

Oh, i want to convert this device to MS-DOS format, and at the Disk utilities , th earase menu didnt have this format! So how should i do it? Please help.