Mybook essential 3tb hard drive

WD External and Portable SSD External SSD for macOS
1

if i format my hard drive to mac, can i still use it on windows?

2

Hello, Windows is not compatible with the default Mac format (HFS+) but you can format the My Book using exFAT to use it on both. Click on the following link for more information. 

http://support.apple.com/kb/PH5819