External 3TB disk only showing 2.2TB

Question

Level 1

6 points

External 3TB disk only showing 2.2TB

I have a iMac (27-inch, Late 2009) running Yosemite 10.10.5 and have attached an external two-drive enclosure which is equipped with eSATA and USB 2 connections.

When I insert a 3TB Seagate Barracuda drive in it and connect via USB2, Disk Utility only reports a 2.2TB drive and no matter how I erase/partition it that is the maximum I can achieve.

If I ask for 'Get Info' on the drive from the Finder it reports 2.2TB Capacity but also shows that there is 867.8MB used which is the missing capacity.

Does anyone have a clue how I can use the full 3TB?

Many thanks.

PS I have two of the 3TB drives and both report the same issue.

Posted on Sep 3, 2015 5:26 AM

Reply

Answer 1

Lexiepex

Level 6

14,102 points

Sep 3, 2015 5:38 AM in response to k3comms

Is this a NAS setup?

800 MB reserved space for "internal" communication

Reply

Answer 2

k3comms Author

Level 1

6 points

Sep 3, 2015 5:54 AM in response to Lexiepex

Thanks for the response.

It's not a NAS just a simple connection to use for storage. If/when I get it to work I intend to try the two drives as a 3TB Raid.

Kind regards,

Dave.

Sent from my iPhone

Reply

Answer 3

Lexiepex

Level 6

14,102 points

Sep 3, 2015 6:11 AM in response to k3comms

800 GB is a bit overdone for internal communication. Was there any Seagate software perhaps on your mac? If so you have to completely uninstall that, it does not work well with OSX, and reserves some space on the disk for itself.

After that you have to restart, then reformat.

Reply

Answer 4

k3comms Author

Level 1

6 points

Sep 3, 2015 6:31 AM in response to Lexiepex

There is no Seagate software on the Mac, this is the first external drive I've connected.

What does puzzle me is the fact that Disk Utility only recognises it as a 2.2TB drive, strange eh?

Reply

Answer 5

Lexiepex

Level 6

14,102 points

Sep 3, 2015 6:40 AM in response to k3comms

Open Terminal (in Utilities)

copy paste the following in it, then enter

diskutil list

what does it say?

Reply

Answer 6

k3comms Author

Level 1

6 points

Sep 3, 2015 6:51 AM in response to Lexiepex

Davids-iMac:~ dave$ diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS DTMacHD 2.0 TB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.2 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_HFS Untitled

Reply

Answer 7

k3comms Author

Level 1

6 points

Sep 3, 2015 6:52 AM in response to k3comms

Sorry, posted without a message ;-)

Reply

Answer 8

k3comms Author

Level 1

6 points

Sep 3, 2015 6:53 AM in response to k3comms

This is more readable!

Last login: Thu Sep 3 14:49:55 on ttys000

Davids-iMac:~ dave$ diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS DTMacHD 2.0 TB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.2 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_HFS Untitled 2.2 TB disk1s2

Davids-iMac:~ dave$

Reply

Answer 9

Lexiepex

Level 6

14,102 points

Sep 3, 2015 7:37 AM in response to k3comms

Indeed, now you see how it is:

210MB for the EFI partition (firmware on your mac)

650MB for the Recovery Partition.

You have formatted as a bootable disk, so that you can also put the OSX on. Or use for cloning with a cloning app, like CarbonCopyClone ( I use that one) or SuperDuper!

Nothing wrong !!

Lex

Reply

Answer 10

k3comms Author

Level 1

6 points

Sep 3, 2015 7:50 AM in response to Lexiepex

Apologies Lex, I should have explained.

disk0 is my factory fitted 2TB internal iMac drive which is functioning perfectly.

disk1 is the culprit - it is a 3TB drive that is only showing as a 2.2TB device unfortunately.

Reply

Answer 11

Lexiepex

Level 6

14,102 points

Sep 3, 2015 8:06 AM in response to k3comms

I am sorry, I looked with my nose, and it was not long enough (as we say here...).

The second, although formatted with the GUID Partition Table, does not have the Recovery Partition.

Format it again as MBR partition table. Same Mac OS Extended (journaled).

Reply

Answer 12

Sep 3, 2015 8:14 AM in response to k3comms

It is likely that your external enclosure does not support 3 TB and larger drives. This is even more likely since the enclosure has a USB 2 interface, which indicates it's an older enclosure.

Check with the enclosure manufacturer, they may have a firmware update for the enclosures controller. If not, you going to need a new enclosure that supports larger drives.

Tom

Reply

Answer 13

k3comms Author

Level 1

6 points

Sep 3, 2015 8:18 AM in response to Lexiepex

I've tried every option to format the drive but each time the largest partition I can create is 2.2TB.

Even if I overwrite the size in Disk Util with 3TB it reverts to 2.2TB when I start the process.

Its as if the missing 868MB doesn't exist.

Reply

Answer 14

Drew Reece

Level 6

10,660 points

Sep 3, 2015 8:28 AM in response to k3comms

Do you have another external drive enclosure or method to connect the disk to the Mac?

To me it looks like a drive controller that only supports smaller volume disk sizes(as Tom said 🙂). You may find that another disk controller reports the full size. Another possibility is to repartition the disk into 2 smaller chunks then see if it shows both halves if you create 2x 1.5 TB partitions. You would need to do that on another Mac or using a different drive controller since you apparently can't get access to the full disk as it currently is.

I'm not sure if using a MBR partition will alter anything, GUID/GPT supports volumes over 2TB, so it should work as is.

Also check the disk for any jumpers, if it has any be sure they are set correctly according to the manual/ spec sheet (search Seagate).

Reply

Answer 15

k3comms Author

Level 1

6 points

Sep 3, 2015 8:25 AM in response to Drew Reece

Thanks Lex.

I do have a FW800 drive attached to my server and am contemplating trying the 3TB in that to see if it make a difference. It has 2x2TB at the moment set up as a 2TB RAID

I'll have a go this weekend and let you know the outcome.

Many thanks for your help.

Reply