Last week, I bought a 4TB hard drive to connect to my MacBook Pro. My quest to have access to all the 4TB on my Mac was more difficult than expected.

After a lot of experimenting, I managed to create an exFat partition of 4TB. (For people who want to replicate my approach: I connected the HD using sata-cables to another computer, and booted the computer from a Windows 8.1 dvd. Next, I created the exFat partition using the partition manager on the dvd. When I started Windows 8, the disk manager showed me that I only had created a partition of 1.8TB. I removed this partition, and created a new one of 4TB. Next, I had access to the full 4TB of my new drive.)

Since OS X also supports exFat, I figured I should be able to see the partition I created on Windows. This turned out to be wrong. When I connected the HD to my Mac using a docking station, the HD was visible in Disk Utility, but there were no partitions associated with it.

diskutil list shows the HDD as follows:

   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.8 TB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1

Now comes the strange part. When I run a Windows 7 virtual machine and connect the HD to this virtual machine, I have full access to the full 4TB.

The only conclusion I can draw at this moment is that OS X Yosemite does not support hard drives larger than 2TB.

I would like to know if other Mac users have had more success than me in connecting a hard drive larger than 2TB to their Mac.

  • 3
    What is the output of diskutil list on the Mac when you have the drive connected? The partition scheme matters as well as the volume format. – bmike Dec 29 '14 at 16:06
  • 1
    I have at least two 3 TB drives attached right now, and OS X is accessing the full space available. They are formatted as Mac OS Extended Journaled, though. It seems more likely to me that the way the drive is partitioned is at fault. – tubedogg Dec 29 '14 at 21:50
  • As @tubedogg has pointed out, any Mac User can access drives larger than 2TB, the question you should be asking is whether a Mac can access a Windows formatted drive greater than 2TB. – amergin Dec 30 '14 at 21:58

The only conclusion I can draw at this moment is that OS X Yosemite does not support hard drives larger than 2TB.

Very wrong. Yosemite supports drives up to 8EB (exabytes. Or 8 million terabytes. You could download the internet with some room left over).

What it has problems with is proprietary file formats from other companies, esp. if the patent holder doesn't want to share.

If you want to access the full drive on your Mac, repartition it in Disk Utility and format as HFS+. If you want to share the data on this very large volume across platforms, the easiest way is a NAS enclosure (Network Attached Storage - basically an external drive with an ethernet port). The disk format only matters to the device it's directly connected to.


I read on another forum that there is an issue with Yosemite reading Windows formatted exFat drives.

I don't seem to be able to find any workaround, so I am faced with the only viable option I can see: which is to copy stuff on disk to a Yosemite formatted hard disk.

I don't know how Windows reacts to Yosemite formatted exFat drives, though.

  • I'd try formatting it on a mac. fat drives have a limit of 2T. so someone has gotten confused. try both partition formats. – historystamp Jun 7 '19 at 1:21

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