Choose the appropriate format:
HFS+ (Hierarchical File System, a.k.a. Mac OS Extended (Journaled)
* Read/Write HFS+ from native Mac OS X
* Required for Time Machine or Carbon Copy Cloner or SuperDuper! backups of Mac OS X system files.
* To Read/Write HFS+ from Windows, Install MacDrive
* To Read HFS+ (but not Write) from Windows, Install HFSExplorer
* Maximum file size: 8EiB
* Maximum volume size: 8EiB
* Mac OS X: Mac OS Extended format (HFS Plus) volume and file limits
* You can use this format if you only use the drive with Mac OS X, or use it for backups of your Mac OS X internal drive, or if you only share it with one Windows PC (with MacDrive installed on the PC)
NTFS (Windows NT File System)
* Read/Write NTFS from native Windows.
* Read only NTFS from native Mac OS X
* To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
* For Mac OS X 10.4 or later (32 or 64-bit), install Paragon (approx $20) (Best Choice for Lion)
* For 32-bit Mac OS X, install NTFS-3G for Mac OS X (free) (does not work in 64-bit mode)
* For 64-bit Snow Leopard, read this: MacFUSE for 64-bit Snow Leopard
* Some have reported problems using Tuxera (approx $36).
* Native NTFS support can be enabled in Snow Leopard and Lion, but is not advisable, due to instability.
* AirPort Extreme (802.11n) and Time Capsule do not support NTFS
* Maximum file size: 16 TB
* Maximum volume size: 256TB
* You can use this format if you routinely share a drive with multiple Windows systems.
exFAT (FAT64)
* Supported in Mac OS X only in 10.6.5 or later.
* Not all Windows versions support exFAT. See disadvantages.
* exFAT (Extended File Allocation Table)
* AirPort Extreme (802.11n) and Time Capsule do not support exFAT
* Maximum file size: 16 EiB
* Maximum volume size: 64 ZiB
* You can use this format if it is supported by all computers with which you intend to share the drive. See "disadvantages" for details.
FAT32 (File Allocation Table)
* Read/Write FAT32 from both native Windows and native Mac OS X.
* Maximum file size: 4GB.
* Maximum volume size: 2TB
* You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB.