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Windows 7: Recover a GPT Partition that became RAW in 3T Internal HDD

29 Mar 2019   #21
RFG

Windows 7 Ultimate x64
 
 

OK, i'm back


Here it is the result of the PW Quick Scan...


Eeeehhhh.... :\




Attached Thumbnails
Recover a GPT Partition that became RAW in 3T Internal HDD-pw9.1cdsk.jpg  
My System SpecsSystem Spec
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29 Mar 2019   #22
jumanji

Windows 7 Home Premium 32 bit
 
 

OK, that means PW sees only 746GB. And that is not even your full first data partition which is 1TB ( approx 1565565871 sectors.)

Now this 746GB seems to be a magic number . If you google 3TB GPT HDD only shows 746GB Raw, you get hundreds of user queries. But they all mean it shows only 746GB in Windows Disk Management. Here it is the reverse. Windows Disk Management shows full 3TB but everything else shows 746 GB. Baffling.

I am now thinking of the following course of action/s.

1. All this started after you reinstalled Windows 7 on a new SSD. The original System HDD is now a secondary drive. Can you go back to the original system? That is take out the SSD, and boot from the HDD as before. See whether all the data partitions on your 3TB disk come alive as before.

2. Use TestDisk for DOS. Make a dos bootable pendrive, boot from it. ( That way Windows does not come into play) If TestDisk sees your full 3TB drive with all 3 data partitions visible, we can possibly recover all data from the first data partition.

Before executing any of this plan, you have to copy all data from the now visible data partitions to another disk. Once we recover the data from the first data partition, you can put the SSD back, wipe the 3TB HDD clean, format it and see whether the full disk is visible without any problems.

Give these propositions a thought and let me know.

I would also elicit dsperber's thoughts on this or any other plan of action since he has been evincing a keen interest on this thread. In yesteryears I had many experts like Slartybart, Anshad Edavana and Kaktussoft chipping in giving valuable support and ideas and many times they made up for my deficiencies but now I am trudging alone.

I am retiring soon today and I shall see you here tom.
My System SpecsSystem Spec
29 Mar 2019   #23
RFG

Windows 7 Ultimate x64
 
 

Quote   Quote: Originally Posted by jumanji View Post
OK, that means PW sees only 746GB. And that is not even your full first data partition which is 1TB ( approx 1565565871 sectors.)

...

I am now thinking of the following course of action/s.

1. All this started after you reinstalled Windows 7 on a new SSD. The original System HDD is now a secondary drive. Can you go back to the original system? That is take out the SSD, and boot from the HDD as before. See whether all the data partitions on your 3TB disk come alive as before.

2. Use TestDisk for DOS. Make a dos bootable pendrive, boot from it. ( That way Windows does not come into play) If TestDisk sees your full 3TB drive with all 3 data partitions visible, we can possibly recover all data from the first data partition.

Before executing any of this plan, you have to copy all data from the now visible data partitions to another disk. Once we recover the data from the first data partition, you can put the SSD back, wipe the 3TB HDD clean, format it and see whether the full disk is visible without any problems.

Give these propositions a thought and let me know.

I would also elicit dsperber's thoughts on this or any other plan of action since he has been evincing a keen interest on this thread. In yesteryears I had many experts like Slartybart, Anshad Edavana and Kaktussoft chipping in giving valuable support and ideas and many times they made up for my deficiencies but now I am tredging alone.

I am retiring soon today and I shall see you here tom.

Hello again jumanji, thanks again for give a little bit of your time to take a look at my problem again. I'm not a HDD expert but i can manage myself with the basics of technology...



As for your first request, i've already did that. It was one of my first tests, replug with stable old system is the best way to see if something is really bad and as i still have the old system intact for now, that was one of my 1st ideas. I've unplugged my ssd, changed to the old system with sata hdd drive as primary drive and only with my 3T drive connected and the partition was detected as RAW, exactly the same as it is now. Something weird happened. I am not infected with any virus (ofc i've also made my virus/malware scans and so... all good)



I'll try TestDisk through usb then. i'll return with feedback when i've done it. Also i haven't tried yet an Ubuntu Live Cd, but i will and check with GParted to see what results come from that approach.


I'll get back here to give feedback when i've done it. I'm a bit busy atm too.


Thanks
R
My System SpecsSystem Spec
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29 Mar 2019   #24
RFG

Windows 7 Ultimate x64
 
 

OK. I'm back again.

Point of situation from my side atm:

+ Backups of the other 2 partitions of the HDD are done.

+ As asked, i've made a bootable dos usb and ran testdisk but as i suspected, testdisk from DOS returned the same results as the win version...
I took a screenshot for you...

What do you think of using bootrec /fixboot from win recovery dvd. I could choose repair option during setup, and run Recovery Console. Then run bootrec /FIXBOOT command to try to fix boot sector. I've read about that in the past, but i got the idea that this solution is only used when one want to restore the system partition. Do you think that it will work with a secondary HD partition like mine?
I'll also try Ubuntu later. Need to rest a bit, i'll be around tomorrow again.
Once again, thanks for all the help.


Attached Thumbnails
Recover a GPT Partition that became RAW in 3T Internal HDD-testdisk-dos.jpg  
My System SpecsSystem Spec
29 Mar 2019   #25
RFG

Windows 7 Ultimate x64
 
 

Dunno what happened here at the forum too, but it seems that my permissions to edit my posts were disabled in the forum... Yesterday was all fine with edits... strange... i'll post this reply insted of adding this thought to the previous post.


However as i cant sleep yet, i was thinking that once i dont have any backup of the MBR/Boot Sectors i can't try to restore it from there but what if we could locate the duplicate of Partition Boot Sector and get information from there. If itss not corrupted too, or missing... its possible to rebuild the PBR from there isnt it? (for what i've read that duplicate is located, in most cases, in the last sector of the volume)
I also read that is no advisable to fixmbr because i'm taking the risk of mess with all partitions again and i dont want to do that at this moment.

Tbh this is where i start sinking in my ability to solve this riddle and i have lack of knowledge to do it by myself...


Off for awhile in a bit...
My System SpecsSystem Spec
29 Mar 2019   #26
jumanji

Windows 7 Home Premium 32 bit
 
 

Hold on for some more time. I shall have my shower, breakfast and return with a response.
My System SpecsSystem Spec
29 Mar 2019   #27
jumanji

Windows 7 Home Premium 32 bit
 
 

I see your tiime is 0236hrs. You can go to sleep now. Whenever you wake up you can see my response. There is no need to do anything in a hurry.
My System SpecsSystem Spec
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30 Mar 2019   #28
jumanji

Windows 7 Home Premium 32 bit
 
 

The devil returns.

"What do you think of using bootrec /fixboot from win recovery dvd."

That is only for fixing the System disk. You can't apply it for non-system disks.

"i was thinking that once i dont have any backup of the MBR/Boot Sectors i can't try to restore it from there but what if we could locate the duplicate of Partition Boot Sector and get information from there."


Your 3TB GPT drive has its protective MBR at sector 0. And this protective MBR will be the same for all GPT drives

Below is a screenshot of the protective MBR.( This drive was initialised as a GPT drive using Windows Disk Management)

Recover a GPT Partition that became RAW in 3T Internal HDD-30-03-2019-11-44-10.jpg

The 16byte green highlighted string is the partition table for a 2TB partition. GPT-unaware programs will read the disk as a 2TB MBR drive so that you know " OMG! this program does not recognise my GPT disk and desist doing any disk operations with it that may muckup and corrupt the GPT partition data.

The four bytes orange highlighted string is the unique ID ( disk signature). It can be any four byte hexadecimal like 0A AA FE 09. No need to bother about this unless the system reports a "signature collision"

Check sector 0 of your 3TB drive with bootice. If it is not the same edit the fields as in the above screenshot and save it to disk. Save the sector before editing so that you can restore it if need be.

Using bootice: My post #7 here: Lost partitions!

( I would think that your disk's protective MBR is not corrupted. To my knowledge if the protective MBR is corrupted the whole disk will become RAW.)

Exercise caution to perform this on the correct disk.

To be continued after a break.


My System SpecsSystem Spec
30 Mar 2019   #29
jumanji

Windows 7 Home Premium 32 bit
 
 

Continuing.......

This morning I was able to fishout a brand new Seagate 3TB Expansion Desktop drive - factory formatted - from my daughter's cupboard and made three 1TB partitions in it.

Recover a GPT Partition that became RAW in 3T Internal HDD-30-03-2019-13-57-42.jpg

If one is going to use a disk only as a data disk, what all is needed in the protective MBR at sector 0 is the 16byte 2TB partition table and the Boot Record Signature 55 AA at the end. ( The 4byte Unique ID also known as Windows Disk signature can be any hexadecimal number including 00 00 00 00)

But if one is likely to use it as a bootdisk anytime, he will be better off wiping sector 0 and initialising it as a GPT with Windows Disk Management with the resulting Sector 0 as in the screenshot in the previous post.

Now coming to the partition structure and its backup:

Sector 1 - The GPT header. Its backup is at the last sector n-1. The backup however is not an exact replica of Sector 1 It is recoded to make the system believe it is coming from Sector 1

If I denote the total sectors shown in bootice as n then the backup is at sector n-1. Here n=5860533167 ( If you start counting from 1, the last sector is actually n-1 and accordingly the last sector will be shown as 5860533166 in the bootice sector field on top )

Recover a GPT Partition that became RAW in 3T Internal HDD-a30-03-2019-16-05-26.jpg

Recover a GPT Partition that became RAW in 3T Internal HDD-b30-03-2019-16-08-34.jpg

Sector 2 - Partition Tables ( each sector can accomodate 4 partition tables.) Here tables for the 128 MB MSR partition and the three data partitions. Its backup will be at sector n-33 =58605333134. The backup is an exact replica of Sector 2

Recover a GPT Partition that became RAW in 3T Internal HDD-c30-03-2019-16-15-51.jpg

Recover a GPT Partition that became RAW in 3T Internal HDD-d30-03-2019-16-25-40.jpg

Sector 264192, Sector 1953685504, Sector 3907184640 Volume Boot Records for the three data partitions at its start sector. (MSR is not user accessible and used by the OS to store data when needed. No VBR)

One Data partition VBR sample:

Recover a GPT Partition that became RAW in 3T Internal HDD-e30-03-2019-16-34-33.jpg


If the GPT Header and the partition tables get corrupted, the system will automatically read from the backup and the disk will continue to perform normally. The user wouldn't even know that some corruption had taken place and the partition data is being read from its backups.

( The corrupted header/Partition Tables will continue to remain as such in their seats. They are not restored with the backups)

Will be continued after a short break


My System SpecsSystem Spec
30 Mar 2019   #30
jumanji

Windows 7 Home Premium 32 bit
 
 

OP: "I'll also try Ubuntu later."

That is a good idea.While any Live Linux distro can be used, we in Seven Forums as well as Ten Forums have used Lucid Puppy. So you may give it a try.

1. Download Lucid Puppy (Ubuntu-compatible Build) version 5.2.8 ISO from Long-Term-Supported WaryPuppy (LTS)

2. Create a bootable pendrive with that ISO using Rufus

3. Boot into Linux and check whether it can access your first data partition.

Go to the topic "Recovering files from the non-bootable Internal drive" in this thread ​Lucid Puppy way to recover files from a non-bootable computer

Unfortunately while Windows sees your 3TB disk to the end, the other programs tried including bootice see only 746GB .

So we need to try everything possible and hope for the best.
My System SpecsSystem Spec
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 Recover a GPT Partition that became RAW in 3T Internal HDD




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