Disk utility is unable to partition a 4TB Seagate or LaCie drive. Is there a compabitiliy prolblwm with Yosemite, the disk utility and partition new large drives?

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Level 1

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Disk utility is unable to partition a 4TB Seagate or LaCie drive. Is there a compabitiliy prolblwm with Yosemite, the disk utility and partition new large drives?

I recently purchased a 4TB Seagate drive to back up my timecapsule and my photos. I wanted to partition the drive into 2 TB each. Disk utility was unable to partition the drive... it grays out immediately after I choose 2 partitions and remains current at one partition. Any ideas why this is happening?

Thunderbolt Display (27-inch), iOS 8.1

Posted on Nov 3, 2014 2:11 PM

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Answer 1

Kappy

Level 10

362,007 points

Nov 3, 2014 2:24 PM in response to rebmonte

Sure it's one single drive and not two or more drives in a RAID array? You cannot partition the latter. Did you buy a bare drive to put in your own enclosure? If so are you sure the enclosure can handle a drive of that size? In any event you need to give us more information than you have.

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Answer 2

rebmonte Author

Level 1

8 points

Nov 3, 2014 2:38 PM in response to Kappy

I just purchased a seagate 4TB external drive and was unable to partition the drive. I was on the phone with seagate for an hours and they couldn't figure out why it wasn't working. I returned the drive and purchase a LaCie 4 TB drive and the same problem occurred. I don't know if it is one single drive or not. How would I find this out?

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Answer 3

Kappy

Level 10

362,007 points

Nov 3, 2014 3:06 PM in response to rebmonte

Start with the model ID/number then look on LaCie's website for a description of the product. How are you attempting to partition the drive? The proper procedure is:

Drive Partition and Format

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to two. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.

This should work unless your drive is configured as a Core Storage device. In that case you need start by selecting the core storage volume (indented entry in Disk Utility,) click on the Erase tab in the main window, then click on the Erase button. This will return to drive to a normal bare state so that you can repartition it.

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Answer 4

rebmonte Author

Level 1

8 points

Nov 4, 2014 1:03 PM in response to Kappy

I did all of the above. It made no difference. I wonder if you are correct that the 4 TB drives are actually two internal 2 TB drives and that is the problem.

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Answer 5

Apr 19, 2015 8:39 AM in response to rebmonte

Had the following experience, somewhat similar

Several 4 TB disks and one 3 TB disk were ok on a Mavericks Mac, disks via an external USB enclosure (Sharkoon)

No problems with 2 TB disks, but big problems with the 3 and 4 TB disks, like described

On a new Mac

The 3 or 4 TB disks were not correct recognised on a new Mac, with new installed Yosemite from scratch

I think the following was the root cause

The USB enclosure (Sharkoon) supports till 2 TB disks, on Mavericks it was more tolerant it seems with 3 and 4 TB disks

On Yosemite they were unusable

I bought a new USB enclosure which supports till 6 TB disks (Mediasonic ProBox)

No problems at all

All disks correct recognised, correct size

Hope this helps

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