Damaged partition table and MBR are the major factors that cause Windows boot issues. Microsoft provides a free utility for recovering your corrupt MBR of hard drive partitioning. The tool will let you repair the damaged master boot record (MBR) or the Boot Configuration Data (BCD).
If you are facing boot problems in the Windows OS then, the first thing you must try is Startup Repair. If startup repair fails to fix the problem then, run Bootrec.exe to fix the issue.
How to repair damaged or corrupt hard drive partition table using bootrec?
- First, boot from the Windows Setup DVD or a System Repair Disc.
- After booting your system, launch command prompt. (From Advanced options or the Safe Mode, this varies according to the Windows versions used).
- Run command exe in command prompt.
The bootrec.exe command is available with four options namely:
- and, /RebuildBcd.
1. To repair the corrupt or damaged boot sector:
Run bootrec.exe /fixmbr
2. To write a new boot sector:
Run bootrec.exe /fixboot.
3. To rebuild the boot configuration data (BCD)
Run bootrec.exe /rebuildbcd.
4. To add missing windows installations to the boot configuration data
Run bootrec.exe /scanos
Which bootrec parameter among the four is to be used and when?
- The errors like “Operating System not found“, “Error loading operating system“, “Missing operating system” or “Invalid partition table” indicates that something went wrong with the MBR and it needs to be repaired. In such situation run exe /fixmbr
- Suppose if the boot sector is replaced with a non-standard Windows boot sector (such as Windows Vista, 7, 8 or 8.1) then it may lead to boot time issues. In such case, running bootrec.exe with /FixBoot parameter could help you.
- If the boot sector is damaged and needs to be replaced then, you should run bootrec.exe /FixBoot command. By running this command, a new boot sector will be written to the system partition. This command proves helpful in several other situations too such as Boot issues occurring due to an installation of earlier Windows operating system after your version of Windows.
- Startup issues can also occur due to damaged files in the boot configuration data. In order to rebuild those damaged BCD files, you need to run exe /rebuildbcd.
- In the case of multiple operating systems installed on your system, one of them or some of them may turn unavailable. This happens due to some missing OS installation files in the BCD. Such issue can be fixed using bootrec.exe /ScanOS command. The command scans for all installed OS on the disks and makes them available to you by manipulating BCD records.
- First, run bootrec /fixmbr to clean the Master Boot Record.
- After that run exe /nt60 all /force
/nt60: This argument specifies the master boot code which is compatible with BOOTMGR.
/all: This argument specifies that the master boot code will be updated on all partitions
/force: This argument specifies that all the volumes will be forcibly dismounted while boot code is updating.
The above commands lead to a new MBR and let the correct Windows boot loader to load the specific Windows installation that was previously unavailable.
You can solve most of your Windows boot/startup problems using the Bootrec.exe. However, it cannot guarantee the fix for the problem. If this fails to recover your corrupt MBR or hard drive partition, then try using advanced hard drive partition recovery tools. These tools are capable of recovering lost/deleted/inaccessible Windows partition data in all sorts of data loss situations.