Most external HDD comes in NTFS format, which means, it work fine on Windows but MAC, the drive will become read-only. Or let say you brought an unformatted HDD. Whatever be the case, if you are only going to use your HDD on MAC, you will have to format it to MAC supported file system — HFS.
However, if you want to use this Hard drive on both Mac and Windows or any other operating system, then there are other workarounds. Like using FAT32 or software like NTFS-3G. This video explains that in detail.
So that being said, let’s see how to format an NTFS hard drive to HFS+ using a MAC.
1. Connect the external HDD to your MAC. Make sure it’s mounted correctly and you can access its content. If there is any data in it, take the backup. Because formatting a drive will also erase the data.
2. Now press cmd+space to launch spotlight and type in disk utility and hit enter. You can also navigate to Go > Utilities. The /Applications/Utilities/ Disk Utility.
3. Under disk utility window, click the of your external hard drive and then click on Erase option at the top of the window.
4. Under Volume, Format drop-down menu, choose Mac OS Extended (Journaled) also give a name (like 2TBHFS) or whatever you want.
5. Next, click on Erase and that’s it. Within few seconds, your drive will be formatted to HFS+. To confirm, unplug your drive and re-plug it, open Finder > click on HDD name and press CMD+I. Under drive format, you should see HFS+.
Now you can use this drive to read and write data on your MAC. Also, see: