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Can a Master Boot Record become "partially" corrupt when you clone a hard drive?


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#1 peterk312

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Posted 03 March 2014 - 03:16 PM

Q: If there's an error with the Master Boot Record (MBR) or boot code on my hard drive, can Windows 7 still load in some cases?

The reason I ask:

I successfully cloned my original hard drive to a new hard drive. Not long after, something went wrong with my original hard drive (I accidentally marked the wrong partition as "active" and could no longer boot) and I decided to fix it by cloning the NEW hard drive back to the original (assuming the new hard drive had the same exact data, including MBR and boot loader). When I did this, I had to edit the MBR with a program called EasyBCD to add the new hard drive as a boot option at the boot menu at startup. Note that I can successfully boot from either hard drive and all appears to work properly. However, is it possible that my cloning procedure created something like a "partially" corrupt MBR on the original hard drive that may lead to problems down the road? Should I run the Windows 7 Repair Disc and use the recovery tools to fix the MBR (even if it isn't broken)?



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#2 peterk312

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Posted 03 March 2014 - 03:35 PM

If anyone's interested, this is the boot info from EasyBCD:

 

EasyBCDMBR1.jpg



#3 TsVk!

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Posted 03 March 2014 - 08:44 PM

I am of the opinion that if the MBR was corrupted it would not work at all. The information contained in the partition is very specific and critical to the function of the machine, and even partial corruption would lead to OS startup failure.

 

I think you're good to go :thumbup2:



#4 Anshad Edavana

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Posted 03 March 2014 - 10:59 PM

 

 

 I had to edit the MBR with a program called EasyBCD to add the new hard drive as a boot option

 

EasyBCD is not a tool to modify or edit MBR. What you are editing is the BCD store ( Boot Configuration Data ) of the installed Windows. 

 

A typical Windows 7 boot process will be like this :

 

MBR --> PBR of Active Partition --> "BOOTMGR" --> "Boot\ BCD" --> "System32\Winload.exe".

 

"EasyBCD" will help you editing and adding entries in to the "BCD". 



#5 peterk312

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Posted 03 March 2014 - 11:08 PM

 


EasyBCD is not a tool to modify or edit MBR. What you are editing is the BCD store ( Boot Configuration Data ) of the installed Windows. 

A typical Windows 7 boot process will be like this :

 

MBR --> PBR of Active Partition --> "BOOTMGR" --> "Boot\ BCD" --> "System32\Winload.exe".

 

"EasyBCD" will help you editing and adding entries in to the "BCD". 

 

 

So then after cloning, what writes the Master Boot Record (Is it the cloning program itself?)

 

 

Two more questions:

 

1. Are you saying that if the OS won't boot, it can't be fixed with EasyBCD if the problem is with the Master Boot Record, The Partition Table, or the Boot MGR?

 

2. (To answer my question) If there's an error in the chain before the Boot Configuration Data, will the system still boot or will it need to be fixed with a Windows 7 System Repair CD? Can your OS still boot if the Master Boot Record, PBR of Active Partition, or Boot MGR are partially damaged?


Edited by peterk312, 03 March 2014 - 11:17 PM.


#6 Anshad Edavana

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Posted 04 March 2014 - 12:53 AM

 

Can your OS still boot if the Master Boot Record, PBR of Active Partition, or Boot MGR are partially damaged?

 

 

No, they are critical for booting and any corruption will prevent Windows from booting.

 

 

 

So then after cloning, what writes the Master Boot Record (Is it the cloning program itself?)

 

Yes, cloning tools like "Macrium" and "Acronis" will duplicate everything in the disk including MBR, PBR , Volume GUID etc.

 

 

 

1. Are you saying that if the OS won't boot, it can't be fixed with EasyBCD if the problem is with the Master Boot Record, The Partition Table, or the Boot MGR?

 

EasyBCD can be used to fix BOOTMGR and BCD store but either one of your Windows should be up and running to use EasyBCD.

 

For example - https://neosmart.net/wiki/easybcd/tips-and-tricks/recovering-windows-bootloader/

 

If you can't boot in to either OS, you may need to manually repair the boot using installation DVD/System Repair Disc.

 

https://neosmart.net/wiki/recovering-windows-bootloader/

 

 

Also the boot disk of Macrium Pro can auto fix most common boot issues.

 

http://kb.macrium.com/KnowledgebaseArticle50168.aspx


Edited by Anshad Edavana, 04 March 2014 - 12:56 AM.


#7 Scoop8

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Posted 04 March 2014 - 08:21 AM

The other members have said it well.  I'm a routine cloner and full-disk Imager and have not yet encountered a non-bootable Target HHD or full-HDD Image restore test.

 

I use 3 tools to clone but mainly use Acronis (2011) since, for some reason, it's the fastest cloning tool of the 3 that I use.

 

- Acronis

- Macrium Reflect (free ver)

- Clonezilla

 

I'm not sure when Macrium and Clonezilla copy the MBR to the Target device but Acronis apparently does that at the end of the cloning process.  I'll see a message that says "Copying MBR..." just before the cloning process completes.






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