Enable writing to NTFS drives
Your Mac can write data to a Windows disk, with a bit of help
OS X can mount drives formatted as NTFS by a Windows system, but, by default, only as read-only volumes. This allows you to copy data from them, but not to add or alter it.
This has the potential to be annoying: let’s say you’re handed a portable hard drive by a Windowsloving friend, for example; you’ll have to admit that your Mac can’t copy your holiday photos onto it thanks to its arcane Microsoft file system. Except, with a little bit of tinkering, it can. Writing to NTFS volumes is disabled by default, but the code lurks in the Mac OS and can be enabled with a touch of Terminal know-how.
The history of NTFS goes all the way back to the 1980s, but it became mainstream in 1993 when it was introduced with Windows NT (hence the name) 3.1 as the default file system. Since then, it’s spread across to Microsoft’s consumer operating systems from the business-oriented NT family.
Windows XP introduced NTFS 3.1, and it hasn’t been developed since, bar a few tweaks (like HFS+, it’s a mature journaling file system with a proven track record that will be with us for some time to come, surely until drives start reaching into capacities measured in exabytes – billions of gigabytes – since its maximum theoretical capacity is 16EB). Under Windows 8, however, this is limited to a mere 256TB.
As Windows’ default file system, it’s frequently encountered if you’re in the habit of exchanging PC files with your Mac. If you frequently find yourself needing to write to NTFS drives, it may be worth your while investing in a thirdparty solution, such as Paragon NTFS (paragon-software.com/home/ntfsmac), or investigating the NTFS-FREE or NativeNTFS-OSX projects on Sourceforge that offer the same sort of functionality as we’re enabling here, but without all the Terminal-typing.
If there’s an NTFS volume mounted on your Mac, you can tell it’s a read-only
Apple can’t be held responsible if enabling NTFS writes leads to any data loss. Be careful!
drive in two ways. Firstly, when you double-click it to display its contents, it opens in a minimal Finder window without the sidebar or header options. Secondly, if you try to copy a file or folder to it, a little white ‘no go’ symbol appears next to your cursor. It’s not quite a red and white British ‘no entry’ sign, but you’ll get the message.
The method we describe here works on a per-device basis – this means you’ll have to do it for each different drive you want to write to, and so should probably be considered as a method of last resort when all others have been ruled out.
There are certainly more convenient ways of writing to Windows drives, in addition to the third-party tools we mentioned above. If you can reformat the drive you want to write to, there’s a safer way of doing things: the exFAT file system. Another Microsoft invention, it’s supported natively by OS X and Windows, as well as some flavours of Linux, and offers similar advantages to the universal FAT32 format as NTFS, namely support for drives larger than 2TB and a more efficient method of arranging data.
ExFAT support arrived on Mac with OS X 10.6.5, and although it’s designed for use with flash storage, it works with traditional hard drives, too. Your Mac will happily format a drive as ExFAT from Disc Utility. Reformatting isn’t an ideal option for an NTFS drive that already has a lot of data on it, however, because it will wipe it – make sure you get the drive owner’s permission first.
It’s worth pointing out before we start that Apple has its reasons for setting things the way it has. It doesn’t support NTFS writes, and can’t be held responsible if enabling them leads to data loss. Take a full backup first, and proceed at your own risk. Ian Evenden