I run an imac and two laptops, one windows 7 and one with windows 8.
Your portable drive will be formatted either for windows or mac
open it in your mac
drag any apps inthe drive onto your desktop where they will be copied and leave them there
exit the drive
open disck utilities and locate your drive
click on partition
partition the disc as you wish, probably best with just one partition to start
click on apply and choose GUID partition
click on ok
then format the disk
choose exFat
then when it’s done click on ok
open the drive again
drag the apps back off the desktop into the drive
then close the drive
you can trash the apps remaining on your desktop
the drive will then work with either your mac or your windows pc
the whole process takes less than five minutes
