I'll discuss the advantages and disadvantages of the other three formats below. Unless you have extraordinary needs, you can safely ignore two of them: Mac OS Extended (Case-sensitive, Journaled) and Free Space. There are several possible file system formats you can use for a USB flash drive, and changing them in Disk Utility is as easy as selecting the number of partitions you want on the drive (usually just one), picking the format you want for the drive, and clicking 'Apply.' Note that this will erase all information on the drive, so make absolutely sure you've got copies of everything before moving forward.ĭisk Utility gives you five different choices for drive formats in OS X Lion.

If the drive is listed as NTFS-formatted, you're going to need to format it to something else if you want full compatibility with Mac OS X. If the drive's format comes up as MS-DOS (FAT) or, less likely, ExFAT, you may be able to simply leave the drive as-is and not bother reformatting it. You can disable notifications at any time in your settings menu.

How do i access usb drive on mac