Changing Permissions

WD External Drives External Drives for Mac
2

Hi, that depends on the format that you are using, to use it on both you can try formatting the my book using the FAT32 file system, check the link below for the steps and keep in mind this will delete all the my book files, so do a backup first. 

http://wdc.custhelp.com/app/answers/detail/a_id/291/session/L3RpbWUvMTM1MTQ0MTU4OS9zaWQvdzFsS3RTOWw%3D