I find it convenient to share files between systems using an external hard drive, including Windows, OSX, and Linux. The challenge is that different operating systems use different filesystems by default. I’ve been using Microsoft’s NTFS as a common denominator. On Linux, package ntfs-3g supports NTFS, and on OSX the procedure described in this article worked fine until recently. One fine day last week after a system software update, my Air lost the ability to write to NTFS. The old procedure to enable write support for NTFS no longer worked.
Apple seems determined to prevent people from having a simple, seamless way to share files with non-Apple systems other than an online service like Dropbox. So, people have to keep coming up with solutions. Here’s how I regained access to my cross-system hard drive this weekend.
At first, I thought it would be best to go with a commercial product, as there would be technical support and legal recourse in the event the product corrupted my data. A foolish notion. I tried Paragon’s NTFS for Mac and decided to purchase it. Unfortunately, I didn’t test it quite enough before making that decision. Fortunately, it was only $20.
The drive was readable and writable by Linux and Windows systems, but on OSX some files could not be opened. The error message was, “<file> is used by Mac OS X and can’t be opened.” There was no obvious pattern regarding which files might be so locked.
On Apple-sponsored discussion boards and online help, there is little to no help for this error. A typical response, as on this board, is “I’ve never heard of such a thing as you describe.” Yet, it seems quite a few real people actually have heard of such a thing.
On OSX you can reset the “in use” flag with the command “chflags nouchg”. In this case, the command had no effect on the observed behavior. I could find no help for this problem in Paragon’s online knowledgebase. Fortunately, there was an item in the knowledgebase explaining how to uninstall, which is not obvious otherwise.
I uninstalled the Paragon product and looked for an alternative. Tuxera offers a commercial package based on ntfs-3g. I installed the older open source version from http://download.cnet.com/Tuxera-NTFS/3000-2094_4-75711169.html. You can also get it from http://macntfs-3g.blogspot.com/2010/10/ntfs-3g-for-mac-os-x-2010102.html“. I will refrain from purchasing the commercial version until I’ve tested it more thoroughly than I did Paragon’s product.
The advantage of the commercial version is caching support, which improves performance considerably. My use case is sharing files across systems that are physically located on the table in front of me, so I would not enable the caching feature because of the risk of data loss when I stupidly unplug and plug the drive between systems without unmounting it properly. So, safety trumps speed in my case. Your needs may differ.
I also had to install the 64-bit version of MacFuse, from http://sourceforge.net/projects/osxfuse/. The version installed by default on OSX is a 32-bit version.
The Tuxera product didn’t exhibit the “in use” behavior I saw with the Paragon product. However, there was a bogus timeout error that occurred at the end of the mount process. The error message reads, “Did not receive a signal within 15.000000 seconds.”
This didn’t seem to cause any problems accessing the drive, although it’s a bit annoying to have to dismiss the dialog box every time. A search revealed that it is the result of a minor bug in a script. Some comments online suggested this could be more than an annoyance if one is using encrypted drives, as it can cause the filesystem to be unmounted. To be on the safe side, I looked for a solution.
The same solution is posted in a couple of places: http://apple.stackexchange.com/questions/20037/ntfs-3g-unmounts-ntfs-partitions-because-it-did-not-receive-signal-in-15-second and https://fernandofig.wordpress.com/2011/08/08/ntfs-write-support-on-osx-lion-with-ntfs-3g-f/. The instructions in the first link are easier to follow, and the supporting explanation is better in the second link.
Today my Windows, OSX, and Linux instances can read and write my shared external hard drives with no problems. We will see what new cross-platform usability delights the next software update from Apple might bring.