If you format a USB flash drive on a Mac it will remove all digital files on the drive and will also allow you to change the file system used on the device, which is how data is organized on the flash drive. The biggest concern when formatting the flash drive is which file system to use and the solution really depends on how you’re going to use the USB. The Mac OS Extended, or HFS+, format is the most common choice if you plan to utilize the flash drive on Apple computers. For the ultimate, cross-system compatibility, the MS-DOS (FAT) system, which is the name Apple assigns to FAT32, should be used. The only real problem is, this will limit individual file sizes to 4GB. For compatible use among the latest versions of Mac and Windows without the FAT32 file size limit, exFAT is the ideal solution.
Ok let’s get started.
First, insert the USB flash drive into your Mac computer’s USB port.
Click the options that read “Finder | Applications | Utilities | Disk Utility.” Alternatively, enter “disk utility” in the search bar and click “Disk Utility” to launch the application.
From there, select the USB flash drive from the left pane of Disk Utility. Make sure to select the root folder and not and indented entry directly under it. Choose the “Erase” tab on the right pane. Click the “Format” drop-down menu and then choose your preferred file system. You can also enter a name for the drive in the “Name” field if you like.
Next pick the “Security Options” if you want to completely erase existing data by overwriting it as many times as you’d like. The more times the data is overwritten, the more secure the format, but the longer it will ultimately take. Make you selection and then click “OK.” Select “Erase” and then “Erase” again in the confirmation window. Depending on the size of the flash drive and the security selection you decide on as well, formatting might take a few seconds or several minutes.
IMPORTANT: Remember that after formatting your flash drive all data present on the device will be permanently erased. Make sure to back up any important data before formatting the drive.