A:Answer Hello Dani, Please be informed that the WD My Passport External drive comes preformatted in NTFS format for Windows OS, However, in order to use the drive for macOS you can reformat the drive with macOS supported HFS+J file system by using this link: https://support-en.wd.com/app/answers/detail/a_id/3879 .In order to use the drive with both Windows and MacOS you need to reformat the drive to exFAT file format by referring to the link: https://support-en.wd.com/app/answers/detail/a_id/20821 .Please be informed that reformatting is a data destructive process, please backup the data from the drive before reformatting it.-Need Help? Please see our "'Contact Us" page for information.