Sector size unsupported... uh - what?

I just got the same error on my external Seagate 3TB USB3 drives. From another post, I thought it might be due to the fact they are GPT format and not MBR. But I just looked at the description of DD11 Home and it says it supports GPT, says it will convert MBR to GPT and GPT to MBR.

Here is the entry from my error log; anyone have any ideas?
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Log Entry Details
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Type: Warning
Date and time: 12/8/2012 1:39:53 PM
Code: 1,048,576(0x100000)
Module: 16
Owner: Admin
Message:
Cannot process 'Disk 4' because its sector size is unsupported (4096 bytes).
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Disks with logical sector size other than 512 bytes are not supported by Disk Director. And Seagate 3TB drives seem to be such. Not to be confused with 'Advanced Format' disks which have 512 bytes logical sector size, just like regular drives, and 4kb only internally.
See also http://kb.acronis.com/content/20297

I checked the bytes/sector per KB20297 on my 3TB Seagate GoFlex Desk USB3 and 3TB Seagate Backup+ Desk USB3 and they both have 4096 bytes/sector.

From http://www.anandtech.com/print/3858 discussing an earlier version of the GoFlex drive: Internally the 3TB drive uses 512-byte sectors, however the GoFlex dock emulates a 4K drive to allow for a single 3TB partition to be created in Windows.

I checked the disk properties and it shows MBR. So USB3 interface converts to MBR with 4k sectors; the SATA drive in the external drive housing is GPT with 512 byte logical sectors.

I checked the disk properties and it shows MBR. So USB3 interface converts to MBR with 4k sectors; the SATA drive in the external drive housing is GPT with 512 byte logical sectors.

A dock can't convert MBR to GPT. GPT and MBR are just partitioning schemes and the scheme is defined by what OS wrote on the disk. The dock only converts sector size to make total number of sectors less than 2 to the power of 32 and allow its full utilization with MBR scheme. If you take the disk out of the dock and attach it via its native SATA interface, it will be unreadable (containing no meaningful data), because all filesystem and partitioning structures rely on different sector size.