I have a 2TB hard drive which has been formatted to be NTFS. I have my Windows 10 machine backed up to it.

I also have a Mac which I would like to back up to it, but I do not want to delete the existing Windows data.

I have created a free space partition in windows using Computer Management -> Disk Management. I now see one Primary Partition which is 1120 GB, and a 732G Unallocated space.

How can I make this Unallocated space become an HFS+ partition?

2 Answers 2


This is a very simple do as you've already done most of the work.

All you need now, is a Partition Manager that support formatting HFS. Google for it or start with this list:


Some things off the top of my head:

  • MacDrive and TransMac. Both have limited time evaluation trials.

  • Live CD of GParted, has HFS support.

And there are several other Partition/ Disk Management tools out there that will do it.

PS: It may also be possible to do it via the native disk/ partition tools on the OS, but probably harder.


Here is another way:

  1. Shrink your existing NTFS external drive.
  2. Create a second unallocated partition.
  3. Name the volume (assign it a drive letter (F:, G:, etc...)).
  4. Format it (again as NTFS) using Disk Management in Windows 10.
  5. Connect the drive to the Mac and load Time Machine.
  6. Select that drive as the backup device and Time Machine will ask to use it and erase it. Of course, there are no files on it as it is just a new partition.
  7. Time Machine will automatically format it to HFS+ (macOS Extended, Journaled) to use as a backup device. All done.

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