
Format a disk for Windows computers in Disk Utility on Mac
In Disk Utility, you can format an external disk that you can use with both a Microsoft Windows-based computer and a Mac. For example, you might want to do this if you use a flash drive to store data files you need to use on your Mac at home and when using a Windows-based computer at school or the public library.
WARNING: Formatting a disk or volume erases all the files on it. Save any files you need to another volume before formatting.

- Go to the Disk Utility app  on your Mac. on your Mac.- If Disk Utility isn’t open, click  in the Dock, type Disk Utility in the Search field, then click in the Dock, type Disk Utility in the Search field, then click . .
- Choose View > Show All Devices. 
- In the sidebar, select the disk you want to format to use with Windows computers. 
- Click  in the toolbar. in the toolbar.
- In the Erase dialog, click the Scheme pop-up menu, then choose a partition scheme. 
- Click the Format pop-up menu, then choose one of the following: - MS-DOS (FAT): Choose this format if the size of the disk is 32 GB or less. 
- ExFAT: Choose this format if the size of the disk is over 32 GB. 
 
- Enter a name for the volume. - The maximum length for the volume name is 11 characters. 
- Click Erase, then click Done.