Mac OS Extended (Journaled) - This is the default file system format for Mac OS X drives.Īdvantages: Formatting your USB flash drive this way will give you full interoperability with Macs. 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. Your new drive should appear in the left-hand column, and clicking the 'Partition' tab will bring up info on the drive which includes its current format. How do you tell which format your brand-new USB drive has? Hook it up to your Mac and launch the Disk Utility app, located in your Utilities folder (which is in Applications). If the drive comes formatted in NTFS, which is the default file system for Windows, you're going to want to re-format the drive because Mac OS X can't write files to NTFS-formatted volumes (at least not without a bunch of extra work that's beyond the scope of this article). The first format, FAT32, is fully compatible with Mac OS X, though with some drawbacks that we'll discuss later.

The overwhelming majority of USB flash drives you buy are going to come in one of two formats: FAT32 or NTFS.

Format a mac computer