Intel-based Windows computers rely on system BIOS (Basic Input/Output System) for loading and executing bootstrap code. Bootstrap routine of BIOS generates 'int 0x19' that loads the first sector of hard drive in memory at 0000:7C00H segment address. First physical sector of hard drive is known as MBR (Master Boot Record) and it contains bootstrap loader code. In some cases, your system refuses to boot due to missing boot code and you can not access the system. This behavior renders all your data, stored on hard drive, inaccessible and cause serious data loss situations. In such circumstances, you need to perform Hard Drive Recovery to fix the problem.
After loading sector zero of the hard drive, BIOS checks that last two bytes of the sector are 55AA. The 55AA is the boot record signature. It is like EOF (End OF File) when sector is read. Boot record signature is required by BIOS to boot the system. In case, this signature is missing, you come across a BIOS-dependent error message, stating:
“Boot Record Signature AA55 Not Found, xxyy Found”
Alternately, you may get either of the below error messages and the system may stop responding:
“Non-System or Non-Bootable Disk”
“Strike f1 to retry boot”
If Microsoft Windows operating system is installed on any logical drive in the extended partition, you receive below mentioned error message after BOOT MENU choice and NTDETECT runs:
“OS Loader 4.0
Boot record Signature AA55 Not Found, xxyy Found.”
In this scenario, your system becomes unbootable and unresponsive. It does not let you access data from hard drive and needs Hard Drive Data Recovery.
This problem may occur due to any of the below reasons:
Disk configuration or inconsistency problems.
File system corruption or missing system files.
You can settle this problem and Recover Hard Drive data by:
Running ChkDsk utility to repair hard drive.
Booting your system in Recovery Console and using Fixmbr command to rewrite MBR.
Format hard drive and reinstall Windows.
Formatting can fix most of the hard drive related problems, but it also has a downside. It removes all the data from hard drive and causes severe data loss. In such situations, you should recover lost data using hard drive recovery software to ensure quick, safe, easy, and absolute recovery.
Stellar Phoenix Windows Data Recovery software successfully recovers lost data from your Windows hard drive in all data loss situations. Designed for Microsoft Windows 7, Vista, 2003, XP, and 2000 operating systems, this recovery software preserves integrity of your data. It supports recovery from FAT16, FAT 32, VFAT, NTFS, and NTFS5 file system partitions.
How to Fix Missing Boot Recover Signature Problem