Question How do I access files on a GPT-formatted external drive?


Feb 17, 2013
A drive from one of my PCs was having issues, so I've placed it in an external enclosure (USB) to troubleshoot from another machine. However, when I plug it in, I can't access the files. Disk Manager says it has a "GPT Protective Partition". How can I access the files? Would I have better luck plugging it in to the original PC?

Update: A little more info:
  • The drive is 3 TB
  • The external enclosure is this one, which claims to support up to 8 TB drives.
Last edited:
The reported size of 16TiB suggests that the enclosure is configured for a sector size of 4096 bytes rather than 512 bytes. This makes the protective MBR look 8 times larger than it actually is.

You need to find a new enclosure that is configured for a 512B sector size.


This is not an uncommon error when taking a GPT drive from SATA to USB and yes, it does have to do with the 512b, 4kb native issue that causes the GPT to assume a protected status. Check to see if your caddy has updated drivers, which has been known to cure the problem

If you cannot read it in the original computer and just copy files, then you will need to either clean and reinitialize if you have backup or use a HDD tool to recover data or potentially convert it to an unprotected state.
Incorrectly reports drives with 512b logical sectors as having 4096b sectors

By Amazon Customer on September 10, 2016

Incorrectly reports drives with 512b logical sectors as having 4096b sectors. This makes a drive partitioned in this enclosure incompatible with a native SATA controller, and a drive partitioned on native SATA incompatible with this enclosure.
Firmware nightmares

By XXX on July 15, 2021

Never could get this to work. You have to update the firmware and it's a hot mess to do so.