Is it possible to use the same external HDD for both macOS and Windows? For example, can I use it as backup storage for both systems?

If so, should it have at least 2 partitions?


I am doing this with TWO External HDs so I can guarantee my advice is correct.

It's possible IF you have (third party) software installed that let's MacOS, Windows, or both READ AND WRITE the other filesystem (the driver's that come with Mac OS are READ-ONLY).

Otherwise you will need separate partitions for each OS. If you are using Time Machine I VERY STRONGLY RECOMMEND you give it a dedicated partition regardless of drivers!

  • Good answer, but I disagree! I would recommend formatting the external drive (unless you're using it for time machine) as ExFAT! This way neither MacOS nor Windows need drivers to access the data! – NoahL Jan 29 '17 at 16:24
  • Depends on intended use. ExFAT was a 4gb file size limit that is sometimes unrealistic for modern file sizes. For example, if the poster wants to share his iTunes library between OSes like I do and has lots of videos the 4gb limit may get in the way. – Bryan Dunphy Jan 29 '17 at 16:29
  • 1
    @BryanDunphy you're thinking of FAT32. ExFat's file size limit (peta/exabyte range) dwarfs the largest drives available. en.wikipedia.org/wiki/ExFAT – Dan is Fiddling by Firelight Jan 29 '17 at 16:32
  • Okay, I don't use ExFAT myself so I got confused. – Bryan Dunphy Jan 29 '17 at 16:35
  • Last point. ExFAT was designed for SSDs and has about 5x SLOWER reading and writing speed on physical disks (like most external drives) than HFS+ or NTFS! – Bryan Dunphy Jan 29 '17 at 16:54

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .