How to Format a Hard Drive For Both Windows and Mac

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Want to use one external drive for both your Windows PC and your Mac? One hurdle you'll face is that, by default, these platforms use different filesystems. Windows uses NTFS and Mac OS uses HFS and they're incompatible with each other. However, you can format the drive to work with both Windows and Mac by using the exFAT filesystem. Here's how.

In this guide we're using exFAT instead of FAT32, another filesystem that both Windows and Mac can read and write to, because FAT32 has a maximum 4GB file size limit whereas exFAT can work with files as large as 16EB (exabytes). exFAT also performs better than FAT32.

You can format the drive from either the Mac or the Windows machine. However, if you want to use part of the drive for OS X's Time Machine backups, you should do this from the Mac, since there's an extra step to make the drive compatible for Time Machine.

How to Format an External Drive in OS X

1. Connect the drive to the Mac.

2. Open Disk Utility. The easiest way to do that is hit CMD and the spacebar at the same time and type in Disk Utility to find the program.

3. Select the drive you want to format.

disk utility

4. Click Erase.

disk utility eraseIf you don't plan on using the drive for Time Machine, skip steps 5 to 11 below and continue with step 12.

5. Give the drive a descriptive name and leave the default settings: OS X Extended format and GUID partition map. These will format the drive in OS X's HFS+ filetype so it will be compatible with Time Machine.

6. Click Erase and OS X will format the drive.

7. With the drive selected in Disk Utility, click Partition.

disk utility partition8. Enter the amount of space you want to set aside for Time Machine. In this example, we're shrinking the Time Machine partition to 128 GB instead of allowing Time Machine to take up the whole drive.

disk utility timemachine partition

9. Click Apply.

10. Select the new untitled partition so we can format it as exFAT for use with both Mac and Windows.

disk utility untitledpartition

11. Click Erase.

12. Give the partition a name and select exFAT for the format.

disk utility exfat partition13. Click Erase to finish.

Your exFAT-formatted drive or partition can now be used for both Windows and Mac. Note that using a drive frequently between Windows and Mac could increase the chances of file corruption, so make sure you have backups of the files on the shared drive and be extra careful about safely ejecting the drive before disconnecting it from your computer.

How to Format an External Drive in Windows

The instructions below are for Windows 10, but other versions of Windows from Windows 7 and up can also format an external drive as exFAT for use with Mac as well.

1. Connect the drive to your Windows PC.

2. Open the Disk Management tool. You can do that by typing "disk format" or "disk management" in Windows search or going to Control Panel > Administrative Tools > Create and format hard disk partitions.

windows disk management

3. Right-click on the external drive's partition or unallocated space you want to format and choose New Simple Volume…

windows new volume

4. Follow the wizard to choose a volume size.

windows new volume size

5. Assign a drive letter.

windows new volume driveletter

6. Choose exFAT as the file system in the Format Partition screen.

windows new volume exfat

7. Give the volume a new name.

windows new volume name

8. Click Next.

9. Click Finish.

windows new volume finish

Windows will format the drive as exFAT and you'll be able to use the drive on both Windows and Mac.

Add a comment
  • Juan Burrows Says:

    Very Good and Useful. Easy to understand the process for a Mac, it is missing WARNING that it must be done with a new or empty hard drive, because if you do it with a drive that already has something in it you will lose everything.

  • Diogo BG Says:

    Sincerely, worst tutorial ever. I don't recommend it to anyone, is outdated and it will only take your time for nothing.

  • Qinisani Says:

    Thank you so much!!
    Best thing if you want to use an external hard drive for both time machine (on mac) and also for use on both mac and windows.

  • Jesse Says:

    I literally lost everything on my hard drive following these directions. Every photo and video from my childhood - gone. I'm SO upset. Please if you have precious documents on your hard drive DO NOT FOLLOW THESE DIRECTIONS

  • Jesse Says:

    After selecting "erase" the hard drive is now "unreadable" by my Mac and now I have 0 access to the hard drive! >:(

  • Pawel Says:

    Thanks a lot for your help! It worked.
    I could not do it myself, but was finally able to partition my drive for both Mac and ExFAT

  • Marc-Andre Says:

    Well explained, Worked perfectly, thanks !

  • Jessica Says:

    Thanks for the explanation. I have 1 problem though and hopefully someone knows this: I would like to save 500GB for the TimeMachine, but there is no way of changing the TB into GB (my Disk Utility has a different appearance than the one in the pictures and the TB is fixed). Should I enter 0,5 TB or is there another way to do this? Thanks for your help.

  • Amy Walsh Says:

    I followed all these steps but the hard drive won't work on my mac?

  • Iamnana Says:

    Will this erase all the data previously stored on my hard drive ?

  • Marlon Ingal Says:

    make sure you choose "Master Boot Record" over "GUID Partition Map" as partition scheme for the drive to work on both platforms. GUID doesn't work on Windows

  • Altaf Pandit Says:

    This is very clear and nice article.Keep it up with this kind of transparent work.

  • Mike Pitman Says:

    William Sanborn ... You can use FAT32 for macs too. only problem is there is a 4gb file size limit for each file.

  • Marcia Says:

    This is just amazing!! Thank you so much!!

  • Rob J Says:

    Great walkthrough! Worked perfectly.

  • William Sanborn Says:

    I followed every step to format my hard drive on my Windows 10 pc. When I clicked the drop down menu next to NTFS, it shows up with "FAT", "FAT32", and "NTFS". What am I supposed to do when exFAT doesn't show up?

  • Youssef Says:

    Thank you very much, this is very helpful

  • Nitish Says:

    Will this erase all the data previously stored on my hard drive ?

  • Krunal Sonpal Says:

    Thanks mate. This is helpful :D

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