Windows Partition Loss Due to Missing Boot Record Signature

Intel based computer systems rely on system BIOS (Basic Input/Output System) for loading and executing the bootstrap code. BIOS bootstrap function generates the int 0×19 that loads first sector of hard drive in memory at the segment address 0000:7C00H. First physical sector of hard drive is known as MBR (Master Boot Record) that contains primary bootstrap loading code.

But in some situations, the boot process might fail due to missing boot record signature. This behavior of Windows computer renders all of your hard drive partitions inaccessible and cause critical partition loss situations. In these cases, Partition Recovery solutions comes for your rescue to retrieve all of the missing, lost or inaccessible hard drive partitions.

After successfully loading the sector zero, BIOS examines that last two types of sector are 5511 as shows on the disk. The 55aa is known as the boot record signature and this is like the EOF (End of File) when sector is read. It is required by BIOS while booting the system. But in case if the boot record signature goes missing, system does not boot up and you come across the following error message:

“Boot Record Signature AA55 Not Found, xxyy Found.”

Alternately, any of the following messages will appear and your system will stop working:

Non-System or Non-Bootable Disk

Strike f1 to retry boot

If the Windows operating system is installed on the logical drive in extended partition, after BOOT MENU choice and NTDETECT runs, below error message might occur:

“OS Loader 4.0
Boot record Signature AA55 Not Found, xxyy Found.”

Microsoft Windows operating system could not boot in such situations due to some hard drive configuration or boot loader issues. In these cases, system could not read data from selected boot drive and thus it become unbootable and renders all of the hard drive partitions inaccessible, causing partition loss.

In these critical conditions, you require a solution that can effectively scan whole hard drive and retrieve all of the lost Windows partitions. This is possible through third party Partition Recovery Software.

These are highly automated applications, which do not require much user interaction for performing Partition Recovery. These software have quite simple and self explanatory graphical user interface, which enables you to carry out quick and easy recovery. The Partition Recovery Software do not alter data on the hard drive as they have read-only and non-destructive conduct.

Stellar Phoenix Windows Data Recovery is the most comprehensive and robust tool to ensure absolute and quick recovery of lost partitions. It supports recovery of FAT32, VFAT, NTFS and NTFS5 file system partitions. This software is compatible with Microsoft Windows 7 RC1, Vista, 2003, XP and 2000.