While the Mac can use a hard drive formatted for Windows, some features may be limited. So it's a good idea to format a new hard drive specifically for macOS.

To format a hard drive before you start using it in Windows, use the Disk Management utility; on a Mac, use Disk Utility.

Mac 911 How to format a USB thumb drive for both Mac and Windows The Mac/Windows-compatible ExFat format allows larger file sizes than the old FAT32.

If you need a USB drive that's widely compatible with different devices, you may want to format it to FAT32. Here's how to do so on Mac and PC.

If you just built a PC, or added a brand new hard drive or SSD to an existing computer, you have to format it before you can actually store data on it. This is called 'initializing' the drive.