can I add an OSX partition (for TimeMachine) to a drive w/ existing NTFS partition?

I have a 500GB external drive. It has a 200 GB NTFS partition with my laptop’s Acronis-generated backup on it. I would like to dedicate the rest of the drive’s space to backup a Mac (via Time Machine).

When I connect the drive to the Mac, I can see/read the NTFS partition, and Disk Utility can see the full size of the drive. My OSX knowledge pretty much ends there. When searching on the Net, I find instructions on starting with an OSX partition, not starting with an NTFS.

Is this going to be possible—and more importantly—easy? The balance I’m striking is the weight/expense/PITA of packaging up two separate drives, so the bar for saying * oh screw it, I won’t bother* is fairly low. But it would be nice to have everything on one drive.



I think it depends on what partition map scheme the drive uses. If it uses GUID, then Disk Utility can resize and add partitions, which can be of any format. You can use the drive’s free space to make an HFS+ (Journaled) partition, which Time Machine should be able to use.

Can you give me a couple search terms to track down how?

As for partition map scheme, it’s a 500GB WD Green drive. I dropped it in a Rosewill enclosure and used Win 7’s Disk Manager to format it. I initially used all the space, but I shrunk the volume’s space down to the current 200 GB.

Attach it to the Mac, and open Disk Utility, and see what is says about the drive (at the bottom of the window, when you select the drive).

Ah, thanks. It’s Master Boot Record.

See if Disk Utility can format the free space (it’s under the partition tab). I don’t think it can under MBR, but it’s worth a try. Be careful - read all the warnings, or you may end up wiping out your existing partition.

That’s about as far as I could get on my own. When I look at the partition tab, “current” is pre-selected. It shows the current volume and a block of free space. All the options are greyed out. It does recognize and accurately portray the size of the free space.

If I change volume scheme to 2 partitions, it splits the entire drive into two equal partitions, both with default volume names (untitled 1,2). The options button is now active, and it’s default is set to MBR–but it appears that going in this direction will wipe the drive.
I have an old copy of Partition Magic around here somewhere. Any idea if it can be used from the PC side of things to create the Mac partition from there?

It’s worth a try.
Just create a new partition, and then mount the drive on the Mac, and tell it to erase that partition. You might want to look at this:

You could also try using a GParted boot disk on a PC* and making an HFS+ partition to take up the rest of the space on the drive. Then see if you can make TimeMachine use the new partition.

*You might be able to use it on a Mac, too. I’ve just never tried it.

T beat me to it, but GParted would be my first tool of choice. Easy to use and it will let you configure the partitions pretty much how you want them (static or dynamic, for instance).