Monday, July 5, 2010

How to recover Corrupted/Compressed BOOTMBR in Windows 7

If you are a long-term Windows user, at least once you might have come across any one of the below errors while booting Windows.

- Unable to load Operating System 
- NTLDR is missing 
- boot.ini is missing

The above errors occur (mostly in NT architectures like Windows XP) mainly due to the
corrupted MBR (Master Boot Record) or NTLDR

Boot process in Windows NT Machines:

In Windows NT machines after the POST(Power On Self Test) the BIOS will access the MBR in the Hard Drive, it is the location where the information about the partitions and paths for the NTLDR(NT Loader) and boot.ini are located, after directed by MBR, NTLDR takes care of the  further process for booting by accessing boot.ini and HAL(Hardware Abstraction Layer, responsible for hardware drivers) but for some reasons if any of the files are missing the boot process will not go further and it will show an annoying message of the screen, like the above mentioned errors.

Boot process in Vista and Windows 7

The boot process in windows Vista and 7  has a  slight change, after POST the further boot process will be handled by BOOTMGR and here we are going to see how this BOOTMGR can be recovered in case of above errors.

How to recover BOOTMGR in Windows 7 or Vista

It's a quit simple process to recover corrupted BOOTMGR, but most of the time without proper understanding most of the users perform incorrect troubleshooting and end up with more issues.


1. Windows XP or 7 bootable CD

2. patience!


- boot you machine from your DVD drive which has the bootable Windows OS

- go to the recovery console and access the machine from Command Prompt
- once you are there, navigate to C : drive and execute the following commands
     bootrec /fixmbr
     bootrec /fixboot
     bootrec /rebuildbcd
- reboot your machine, this will fix the issue in most of the cases

Thanks for reading!

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