If you don't mind formatting it, connect the HDD, open Disk Utility (Spotlight will find it for you) and format (ERASE) it with the MS-DOS Filesystem, which is Apple's name for FAT32.
If you don't mind formatting it, connect the HDD, open Disk Utility (Spotlight will find it for you) and format (ERASE) it with the MS-DOS Filesystem, which is Apple's name for FAT32.