Formatting External Hard Drives In OS X [Video How-To]



When you buy an external Hard Drive for use with Time Machine, Apple’s backup software, you will most likely need to format it before you can use it, since chances are that it is formatted for a Windows based computer. You could always spend the extra money to get a Mac formatted Hard Drive, but what’s the sense in that? You can format your own external Hard Drive right from Mac OS X. This video will show you how.

  • Jeff Schader

    If you actually tried formatting the enclosure label you have highlighted in the image you would end up getting an POSIX error I think. You have to format the volume names below it. I’ve had this happen to me numerous times.

  • Chris

    I gotta switch to windows. then I could learn something new in how-tos

  • besweeet

    This article made me laugh. Really? Should people really need to lookup a tutorial on how to format a hard disk? Must be that Mac lifestyle, I suppose. Glad I got out of it.

  • Beware

    The proof everyone can be a cult of mac author.

  • Michael Steeber

    Actually, I looked at the Google search suggestions for Mac How-tos, and this was one of the most searched, so I figure a lot of people must want to know about it.

  • besweeet

    Which should tell Apple that they should make it a little easier to do. Although Mac users should just figure it out themselves.

  • CalicoAvenger

    I have one beef with buying Windows-formatted external drives. I have a WD 750GB drive (FAT), which I wanted to reformat to use for backup clones (I clone before and after OS X updates; different partitions for before and after). It would NOT let me reformat it, I got some strange error message (was over a year ago, so I don’t remember exact message text) that because the (USB) drive had a MBR, it could not be reformatted. It would not even let me partition the drive so I could partition it and format those partitions as I wished (my second thought).

    So now I have a drive which cost approx $100 at the time, sitting around useless. Siblings (both also Mac users) didn’t want it, and drive prices are so low that I can’t even see being able to sell it. The drive’s box HAD NO ADVISORY that it could not be partitioned or reformatted, which is what really ticked me off.

    Since then, I have bought a nice 1TB drive( Mac-formatted) for my cloning. Figure the extra cost (for Mac-formatted) is less than the cost of an unusable drive.

  • Jeff Schader

    I buy Windows formatted drives all the time. You shouldn’t have an issue with it. You have to work with the volume part not the main drive name when you’re in Disk Utility.

  • besweeet

    Ah, typical clueless Mac user. A hard drive is a hard drive. Format it as GUID and you’re fine, although OS X can easily read and write to and from MBR drives.

  • CalicoAvenger

    well I expected to be able to reformat it. Reason I even bothered to try to do so was because I wanted to be able to use it for my clones … if I just wanted to copy files to it, I would have left it alone as a FAT drive. However I have a network FAT drive I can use for that from both my desktop & laptop.

  • Dilbert A

    This comment made me laugh. Really? Now your changing your argument? Should people really be complaining about a tutorial on how to format a hard disk? Must be that besweeet a troll, I suppose. Glad you got out of it.

  • jeffsters

    They do. If you plug in a non-formatted drive the OS will alert and offer to format. If the drive is formatted Fat32, etc., the OS will mount it. Not a good idea to offer to destroy data. In other words it does EXACTLY as it should.

  • nthnm

    I used an external hard drive with an HP laptop and then later switched to a Mac and continued using the same hard drive with Time Machine and didn’t have a problem.

  • Barbara Jackson100

    This is somehow 3 mins video and you make it 6min….i would luv to see “How to clone a Mac hard drive using Disk utility” video thats imp than this video..

  • besweeet


  • Catherine

    Thank you Michael for this tutorial! Very useful for many people like me.

  • Matt

    Brilliant, thank you so much!!
    Got a LaCie Porsche Portable hard drive today and when it said it wasn’t compatible with OSX Lion i was worried about having to return it. Thanks bro!

  • mattsmansfield

    Very helpful – I needed to know which format to use when erasing. :)


  • Paul James Nicholson

    where did the post go that took me half an hour? i was interrupted to login. does that mean its deleted?

  • Paul James Nicholson

    Why would anyone CHOOSE to make their Hard Drive incompatible with Windows? 99% of computers use windows. If your computer gets stolen or even if you want to share files, a Mac-only external drive renders your hard drive useless in an emergency for data recovery and getting a job completed on schedule at 4am. If formatted for Windows, there are probably 500 windows machines in a square block that you could read the files from.