If you want to use your external hard drive in both windows and Mac OS then we need to change the format of the hard drive. I am using WD hard drive that comes with the default NTFS format and that is supported in the windows machine only.

If we will format in HFS+ format then it will be supported in only mac OS.

I would suggest you to format it in exFAT format. That is supported in both mac and windows OS. It is not supported in older versions of Windows like Windows XP etc. But I believe we are not using this older system nowadays.

Steps to format hard drive in Mac:

  1. Open disk Utility.
  2. From the left column, select your hard drive.
  3. Click on the erase button on top.
  4. Type the Drive name and select the desired format, in our case select exFAT.
  5. Click on the erase button.

Now you can use your hard drive on any device mac or windows.