3TB HD inaccessible externally via eSATA or USB

[aleph99]

I have a 3TB data disk (formatted as GPT) that worked flawlessly with my i7 PC running Windows 7 64-bit. Recently I decided to move this HD to external storage using an eSATA dock station. The OS still recognized the HD and I was able to read its folders, but many files became inaccessible and generated an error. The same happened when I connected this HD via USB using an external enclosure. When I reconnected the HD to the PC using the internal SATA cabling, everything went back to normal.

The next step was trying to reformat the HD. While connected via SATA, I can format the full 3 TB. When connected externally, Windows only "sees" 2 TB, so no deal.

Apparently there is a 2TB limitation to external HDs, even when connected via eSATA. However, I also have an external USB HD with 4 TB that can be accessed normally, so there must be a catch somewhere. I would have thought that eSATA is just a passthrough connection for external HDs with the same features of internal SATA, but apparently this is not the case.

Is there any trick to circumvent this 2TB limit for external HDs? Would my problem possibly be caused by limitations of the external eSATA/USB hardware, since I able to access the other 4TB HD that came from the factory with its own enclosure and USB cabling?

 

[Paperdoc]

I suppose it's possible that the external enclosure's USB3-to-SATA electronics could limit its abilities. However, I would expect (can't be SURE, though!) this would not be the case for an eSATA connection because most such are straight pass-through, as you say.

If you have not, check details of power supply. I suspect (but you don't say) that the HDD in question is a standard 3½" unit designed for use internally in a desktop machine. Such units always need more power than a USB2 port can provide, and most need more than even a new UB3 port can provide. If you are using the eSATA connection system, note that most (excepting some non-standard ones) provide NO power to the external device. When using in eSATA mode, you MUST use the external power supply module provided with the enclosure. And because of the USB3 power limitations, I really suspect you need to be using that "power brick" in that mode, too.

Remember, too, that with such an enclosure you may connect and use ONE of the two possible data paths, but not both. So you should disconnect the one data connection cable you are NOT using.