What is the best way to format an external hard drive in Mac OS X Lion?

Nishith Parikh May 4, 2012

I want the hard drive to offer the following, in order of priority.

1) 2 partitions- one for Mac (Lion) and the other for Windows (7);
2) Backward compatible bootable for both platforms on other computers;
3) Can back up the computer (running lion) HD via time machine;
4) Can store images of other HDs for future recovery.
5) Can run either system applications on Mac (Lion)

  1. VictorGeis
    August 27, 2012 at 6:17 pm

    In order to use your partition with Time Machine, you will need it to be formatted HFS. As for the Windows partition, the best bet is have ExFat. Though I would suggest getting NTFS support on your Mac and format the Windows partition with that.

  2. Tim Lewallen
    May 7, 2012 at 2:32 pm

    Try formatting the drive in ExFAT. This format can be read by and written to by both Mac OS and Windows computers. You can format the drive via the Disk Utility built into Mac OS.


  3. Mike
    May 4, 2012 at 8:09 pm

    1. I suggest to format it within Mac OS X using Disk Utility: select to create 2 partitions, one in HFS+ the other on either with no file system or FAT (you will be able to format it as NTFS during the Windows installation. At the bottom click on "Options" and select "Master Boot Record" as partition scheme.

    2. Backwards compatibility is limited by the operating system. Lion only works on Intel Macs. Windows 7 should work on most older hardware - however, as someone already pointed out an installed Windows operating system is not plug-and-play with other hardware.

    3. Time Machine requires a HFS+ partition other than the boot drive. If you want to backup to the same hard drive you will have to create 3 partitions.

    4. In general there is no problem storing images on the drive for future recover as long as the recovery software you are using can access the file system where the images are stored.

    5. Explanation? Lion can run all applications supported under Lion. If you want to run Windows programs under Lion you will have to install a virtual machine like VMware, Parallels or Virtual Box and make another Windows installation within those.

  4. ha14
    May 4, 2012 at 9:40 am
  5. Bruce Epper
    May 4, 2012 at 2:39 am

    Because of hardware-specific drivers, you will not find a whole lot of success with booting Win7 from that drive on other machines unless they are using the same hardware (identical machines in a corporate setting?). I'm not sure if the same thing applies to Mac OS X.

    Because of item 4, you probably would want 3 partitions using one of them just for data and/or other HD images.

    As far as the sizes of the partitions, it would depend on how you intend to use the operating systems, what apps you plan to have installed, and other factors. You may want to keep them as small as possible. (I use several VHD files to boot into other setups on my machine that are 40GB which is more than enough for the development and testing I do on them, but there are not many apps installed on any of those.)