Most of the Windows cannot start due to MBR damage, and repair requires the installation media to enter the recovery environment. First, use Windows to install USB or CD to restart the computer, and adjust the BIOS/UEFI startup sequence; secondly, select "Repair Computer" to enter the command prompt; then execute the three commands bootrec /fixmb, bootrec /fixboot and bootrec /rebuildbcd to repair MBR, boot sector and BCD; if an error is reported, run chkdsk /r first to check disk errors. In addition, you should also pay attention to whether it is UEFI startup mode. At this time, the EFI partition should be repaired instead of MBR. If you still cannot start, you can try to confirm the active status of the hard disk, the integrity of the partition structure, the secure boot settings, or use the help of TestDisk and other tools to troubleshoot problems.

Windows does not boot properly, and sometimes the problem is that the master boot record (MBR) is corrupted or tampered with. In this case, the system may directly report the error "Missing operating system" or simply stuck in the boot screen. Fixing MBR is one of the key steps to solve this type of problem.

Use Windows installation media to enter the recovery environment

To fix MBR, you first need a Windows installation USB or CD. After inserting, restart the computer and boot from the media. This step may sometimes be stuck due to BIOS/UEFI setup problems. If you have not changed the startup sequence before, it is recommended to enter the motherboard settings to manually switch the startup device.

Once you successfully enter the installation interface, select the language and click "Next", and then click "Repair Computer". Then you will see the path "Troubleshoot → Advanced Options → Command Prompt". After entering the command prompt, you can start the repair operation.

Repair MBR with command line tools

In the command prompt, enter the following three commands:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /rebuildbcd

These commands are responsible for writing new MBR, repairing startup sectors, and rebuilding startup configuration data (BCD). If one of the commands reports an error, such as "The system file cannot be found", it may be that there is a problem with the partition status. You need to use chkdsk /r to check the disk error before trying again.

Note: If you are using UEFI startup mode instead of traditional BIOS, then MBR is no longer working. At this time, you should consider repairing the EFI system partition instead of traditional MBR.

If it still fails to start

Sometimes even if the above steps are performed, the system still cannot start normally. At this time, you can try the following directions:

• Confirm whether the hard disk is recognized as an active disk
• Check whether the partition structure of the hard disk is complete
• Check if Secure Boot is enabled, which may prevent non-signature systems from loading in some cases

You can also try using third-party tools such as TestDisk or professional PE tools for further diagnosis. However, for most ordinary users, using the Windows-owned method first is enough to deal with most situations.

Basically these methods. Repairing MBR sounds a bit technical, but as long as you follow the steps, it is actually not complicated. It is just easy to ignore the startup method or misoperation, resulting in invalid repair.

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