GPT Protective Partition?

[GTP]

What is a "GPT Protective Partition?"

I've been waiting for a backup to complete (about 1.55TB) for over 3 days. It finally completed but the backed up data is "corrupted and unreadable."
I removed the 2 TB Seagate drive from its box and put it on a sata port.
It's not recognised in Windows but disk management sees it as "GPT Protective Partition."
No drive letter is assigned.

I don't care about the data or the drive, (it's all mine and I have multiple copies elsewhere) so I fired up MiniTool Partition Expert which recognised it as a 1.82TB GPT Partition and a 478mb NTFS Partition.

Just for my edification I started a "partition recovery" on it. We'll see what that does.

Just curious about the description. Time for some googl'n.....

 

[GTP]

Hmmm...so Google shows me plenty of ways to convert the disk to MBR using EaseUS Partition Manager which won't destroy any data on the drive.
Plenty about Diskpart but that's destructive.
I have EaseUS Partition Manager Pro, so I'll try that and see if it works. Just for fun....

@add: Cant find any information about what a GPT Protective Partition actually is or why it happens...
During the backup, day before yesterday, O&O Syspectr gave an alert about temperature.
20/08/2018 07:48 pm Temperature of hard disk USB1 has reached a critical value!

I wonder if that caused it to fail?

 

[Diggs]

GPT is usually a conscious choice, not one that happens automatically somewhere. It's required for Windows RAID arrays across disks but I admit I know very little about the details.

 

[GTP]

I was just reading about GPT vs MBR. The limitation of MBR's 2TB partitions and why Windows favours GPT to allow much better options for large disks.
GPT Protective Partition might be a Seagate thing?

 

[Altster]

I was just reading about GPT vs MBR. The limitation of MBR's 2TB partitions and why Windows favours GPT to allow much better options for large disks.
GPT Protective Partition might be a Seagate thing?

Did you see this:?

https://www.computerhope.com/jargon/g/gpt.htm

 

[Markverhyden]

What version of 'doze are you running? I've run into this twice but can't remember what I did. But the below does sound familiar.

Why does the GPT have a Protective MBR?
The Protective MBR protects GPT disks from previously released MBR disk tools such as Microsoft MS-DOS FDISK or Microsoft Windows NT Disk Administrator. These tools are not aware of GPT and do not know how to properly access a GPT disk. Legacy software that does not know about GPT interprets only the Protected MBR when it accesses a GPT disk. These tools will view a GPT disk as having a single encompassing (possibly unrecognized) partition by interpreting the Protected MBR, rather than mistaking the disk for one that is unpartitioned.

From - https://social.technet.microsoft.co...protective-partition?forum=win10itprohardware

 

[Alexey]

GPT protective partition occupies the entire disk and signals to MBR-only tools that the entire disk is occupied and not to be messed with.
Otherwise, MBR-only tools would have treated the disk as blank, being not aware of GPT.
This is because GPT disk technically still has a valid MBR.

Normally, you should not see that protective partition in MBR if GPT is OK, because there is no need to show it to you.

I strongly suspect accursed silent sector size conversions in USB converter are to blame.
Because this

I removed the 2 TB Seagate drive from its box and put it on a sata port.

rings a loud bell. No, not loud enough. More like LOUD bell.

 

[nlinecomputers]

GPT is usually a conscious choice, not one that happens automatically somewhere. It's required for Windows RAID arrays across disks but I admit I know very little about the details.

GPT is also required for UEFI secure boot. Any new install of Windows 10 on modern hardware is going to have a GPT partition.

 

[Alexey]

GPT... is required for Windows RAID arrays across disks but I admit I know very little about the details.

Actually I don't think so. In Windows, here are MBR basic, GPT basic, and Dynamic disks. Dynamic can be created based on MBR or GPT, so effectively you can have, on the on-disk-structure level, the MBR-Dynamic or GPT-Dynamic disk. To create a Windows software RAID, you need Dynamic disk, either MBR- or GPT-based. I'm not sure what the requirements are for Storage Spaces, but Storage Spaces may well require GPT (in effect, the protective partition in GPT, covering the area allocated to Storage Spaces in a way similar to "GPT Protective Partition" covering the area allocated to GPT in MBR).

 

[Markverhyden]

GPT is also required for UEFI secure boot. Any new install of Windows 10 on modern hardware is going to have a GPT partition.

Maybe original OEM's. But if it's a re-install or a BTO type thing you don't have to unless you want the whole boot disk to be more than 2tb.

 

[nlinecomputers]

Maybe original OEM's. But if it's a re-install or a BTO type thing you don't have to unless you want the whole boot disk to be more than 2tb.

Secure boot doesn't work with MFB partitions. If you want secure boot you have to have GPT. This is a requirement for UEFI Bios. However, having said that there are bioses out there that violate the stated standard and support a modified Secure Boot with MFT and some legacy modes will still boot GPT. They are not supposed to but they break the rules and do so anyway.

 

[Markverhyden]

Secure boot doesn't work with MFB partitions. If you want secure boot you have to have GPT. This is a requirement for UEFI Bios. However, having said that there are bioses out there that violate the stated standard and support a modified Secure Boot with MFT and some legacy modes will still boot GPT. They are not supposed to but they break the rules and do so anyway.

True. But I have yet to run into a machine that only has UEFI. So far they still have legacy as an option.

 

[nlinecomputers]

True. But I have yet to run into a machine that only has UEFI. So far they still have legacy as an option.

Yes, but I have seen several that will not boot in Legacy mode if the system is partitioned GPT. It's a common problem. You need to boot from your USB drive so you have to set the system to legacy and turn off secure boot. Then you have to change it back in order to boot from the HDD again. Which is how it is supposed to work.

 

[GTP]

What version of 'doze are you running?

Thanks for the link @Markverhyden I'll read it thoroughly.
I was copying data from Win 7 Home to 2 TB USB external. (about 1.55TB)
O & O Syspectr reported twice that the temperature threshold had been reached so I suspect that's what killed it.

GPT protective partition occupies the entire disk and signals to MBR-only tools that the entire disk is occupied and not to be messed with.
Otherwise, MBR-only tools would have treated the disk as blank, being not aware of GPT.
This is because GPT disk technically still has a valid MBR.

Normally, you should not see that protective partition in MBR if GPT is OK, because there is no need to show it to you.

I strongly suspect accursed silent sector size conversions in USB converter are to blame.
Because this rings a loud bell. No, not loud enough. More like LOUD bell.

Thanks for the explanation @Alexey
I have a basic understanding of MBR/GPT partitioning schemes, but had never come across a GPT Protected Partition.
Google has loads of information on how to correct/recover/from etc but nothing on what a "GPT Protective Partition" actually is or why it's created.