I have just updated to Mountain Lion 10.8.2; I have done a clean install.
Now after I have installed all my apps and configure them I would like to create a Time Machine backup; so I could have the image of a fresh clean mac :D

The problem here is that I have only one external HDD (1Tb, NTFS formatted and MacFuse installed, so there's no problem in read/write the volume) and half the disk is used with my docs, pics, music, etc.

Is it possible to create a Time Machine backup without erasing the previous contents ?

Will Time Machine save the backup just as easy as copying a disk image to the HDD without erasing my files? Or will it reformat the disk?

Greetings and thanks for the help :D


Time Machine requires an HFS+ partition on the drive, it can't use an NTFS formatted one, even with MacFUSE installed. The way to do this would be to shrink the NTFS partition, then make a new HFS+ formatted partition to use with Time Machine (you can do this with Disk Utility). Unfortunately OS X can't resize NTFS partitions, you'll need to use a Windows machine to do it, then use OS X to create a new HFS+ partition.

  • I think I voted a bit prematurely, because there's no option in Disk Utility to use the free space as HFS+. Selecting the free space I just created at the end of my disk only says that it will be left as unused space. – Andreas Jan 2 '14 at 13:43

You could in theory shrink the NTFS partition and open space for a HFS+ partition, but it is tedious and error prone, and I strongly recommend against it (especially since you have data you would like to keep on the disk already).

Buy a new, separate disk for Time Machine alone.

  • At first when I read this I thought "how hard can it be?", but after starting the Disk Utility in 10.8 I can only confirm that it's not capable of much. Seemingly not even creating a partition from unused space. – Andreas Jan 2 '14 at 14:18
  • @andreas most likely because the disk was not formatted by Disk Utility. – Thorbjørn Ravn Andersen Jan 3 '14 at 15:15
  • Disk utility does magic to discern what drives it has partitioned and hasn't? That sounds unlikely, if it can read MBR correctly then shouldn't that be enough? It gives the impression of being able to handle both MBR and GPT, but my best guess is that Disk Utility just can't manage MBR drives, sad as that sounds. – Andreas Jan 3 '14 at 18:38

You could check out Paragon Software. They have a driver that allows you to do all read and write functions to a NTFS disk. I use it all the time and it seems to work perfectly. You can read about it at the following link: http://www.paragon-software.com/home/ntfs-mac/features.html


Yes, you can put a Time Machine backup on an existing NTFS disk. You need a read/write NTFS driver (the 3 I know of are Tuxera, Paragon & OSXFuse+NTFS-3g), and you need to create a sparsebundle disk image with a specific .plist file inside. Then it works.

Once you have the NTFS driver, it will take you about 2 minutes. Detail instructions + script here: http://www.cafe-encounter.net/p1847/use-a-windows-ntfs-or-linux-or-other-formatted-disk-for-apple-time-machine-backups


The best way to proceed, imho, would be to resize the NTFS partition and create a HFS+ one on the same disk, so you could keep your files in place while having a partition dedicated exclusively to Time Machine.

HOWEVER, it seems that you actually can use a dedicated NTFS partition if you REALLY need to (In case you use a router that supports NAS and does not support the HFS+ file system nor the AFP protocol, for instance. Further, I say "REALLY need" because it is unsupported and someday this workaround may stop working with further releases of OS X, apart from not performing as good as a native solution [although it seems that it does not perform bad either]).

I guess you could try following the steps found here: http://zerga.dyndns.org/wordpress/2011/10/13/howto-get-macosx-lion-time-machine-to-backup-on-a-samba-share/ using your NTFS partition instead of the Samba share mentioned. I Have still not tried this, but I heard of some people who managed to get this working somehow. I will personally give it a try later today. :-)

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