Seagate Backup Plus Portable
4 TB
Seagate Backup Plus Portable
4 TB
Works and is quite easy to set up.
The question is not complete, but I assume that data is to be exchanged between the two systems. So you need to choose a file system that can be read by Mac & Microsoft. e.g. exFAT (or FAT32).
Here is a detailed guide:
www.laptopmag.com/articles/format-drive-for-windows-and-mac
No, it doesn't work quite that simply. Mac has a different file format, but lets you access the NTFS with certain additions. See for example: www.randombrick.de/ntfs-festplatte-unter-mac-os-x-yosemite-b... or www.frisch-gebloggt.de/itgadgets/externe-festplatte-am-mac-d... I would advise you to use two disks to avoid problems or loss of data.