How to Format an External Hard Drive for Mac

Many external hard drives can be used with Windows computers. If you want to connect an external drive to a Mac computer, you may need to format it first. Here are the steps:

How to format a hard drive for Mac

Note – If your external hard drive has been used on a computer, make sure you backup all files. All data on your drive will be lost if you format it.

1. Connect an External Hard Drive to your Mac. To work, some external hard drives must be connected to an outlet.
2. Click the first option in Spotlight Search. You will be able to see all of the external and internal drives connected to your Mac by opening the Disk Utility app.
3. Click View in the upper-left corner of your window to select Show All Devices.
4. Select the external hard drive that you wish to format. This can be found on the left-hand corner of the screen under External hard drives. Select the highest option from the external tree to get the best results.
5. Click the Erase button in the top menu. A small window will appear advising you that the erased drive will permanently delete all data on it.
6. Select a name, format and scheme to describe your drive . You can choose any name, but you should use GUID Partition Map in most cases. You can however choose from the following formats:
   • Mac OS Extended (Journaled), which is compatible with all Macs, is the best choice for most Mac users.
   • APFS (Apple File System), is only available for Macs with macOS 10.13 and later.
   • ExFAT works with Mac and PC.
   • MS-DOS (FAT), is compatible with Mac and PC. However, you cannot transfer files larger than 4GB.
7. After you have completed the setup details, click on Erase. This will instantly wipe your entire drive.

You may get an error message saying “Erase process has failed.” Don’t panic if you get an error message that says “Erase process has failed.” This is a problem caused by Time Machine running in your external drive.

Time Machine must be turned off. Open System Preferences, and uncheck the box next “Back Up Automatically.” Next, click Options besides the “Show Time Machine” menu bar. This will open a new window. You can cancel the Time Machine by clicking Cancel.

Restart the Time Machine after you have turned it off.

How to partition an external hard drive on Mac

Once you have formatted the drive, you can partition it. This will allow you to split the drive into two different formats. This option is ideal for those who use Macs or PCs and want to transfer files with an external drive between different operating systems. Here’s how you do it:

1. Use Disk Utility to select the drive you wish to partition. Click View > Show All Devices to select the disk and not a container.
2. Select Partition from the top menu.
3. Next, click the plus sign at the bottom of the pie chart. A new partition is created each time you click the plus sign.
4. Select a name, format, and size for each of the partitions. Drag the white dots along the edge of the circle to change the dimensions of each partition.
5. Click Apply.

Why partition a hard drive?

You can partition an external hard drive to create separate drives for Mac, Windows, and other operating systems. You don’t need to buy hard drives for each computer.

A partition gives you an area for your Time Machine backup files or a bootable copy of your operating system. You can also protect your data in the event that your drive is infected by malware.