Introduction of MBR
MBR, short for Mater Boot Record. It is a special type of boot sector at the very beginning of partitioned computer mass storage devices. The content of MBR was publicly introduced in 1983 with PC DOS 2.0. It will be created when you create the first partition on the hard drive. MBR contains the Partition Table for the disk and a small amount of executable code for the boot start. Without a valid MBR, it’s impossible to boot the system from the hard disk. If the MBR has something wrong, it may prevent the system from booting. MBR does not belong to any operating system and it cannot be read through disk commands provided by operating system. But it can be modified and re-written through the command. MBR may be affected by malicious code, become corrupted by disk errors, or be overwritten by other boot loaders when experimenting with multiple operating systems on a host. Those viruses and programs can usually cause MBR damaged.
When do you need to repair MBR?
Master Boot Record (MBR) belongs to boot record, along with Boot Configuration Data (BCD). Sometimes you may get the error message like “Operating System not found” or “System missing”, and you may not able to boot your system at all. Such errors are most likely caused by damaged MBR. At this time, you need to rebuild or repair corrupted MBR in Windows 10/8/7 to fix the issues. Mostly, the MBR problem may be caused by malware infection, or improper shutdown. Some external hard disk may also encounter corrupted MBR.
How to repair MBR?
Here we provide you two effective ways to repair MBR as the following content shows.
Method 1. Repair MBR via Windows Installation Disk
If you have a Windows installation disk in hand, you can repair MBR of the drive easily.
1. Connect the external disk to your computer. Shut down the machine and insert the installation disk. Then boot from the disc.
2. Select time, language and keyboard input, click next.
3. After that, click Repair your computer in the lower-left corner.
4. Press Shift + F10 key combination to call out Command Prompt.
5. Type the drive letter of your external hard drive partition at the prompt, like F: , followed by a colon and press Enter.
6. Type these commands in sequence and press Enter after each.
7. Restart the machine when it completes.
If Windows falls to the internal disk, you’ll need to change boot priority to the installation disk in BIOS.
If Shift + F10 combination does not work, try this approach with the installation disk.
Method 2. Easily repair damaged MBR with MBR repair tool
In addition to repair MBR via Windows Installation Disk, you also can use a powerful third party MBR repair tool to repair the damaged or corrupted MBR. Here I highly recommend AOMEI Partition Assistant – An useful partition software which provides you many powerful functions like Rebuild MBR. With the feature Rebuild MBR in AOMEI Partition Assistant, you can easily solve the problem of how to repair MBR.
Before you do:
1. Connect the hard drive to a valid Windows PC which installed AOMEI Partition Assistant (you can download AOMEI Partition Assistant Standard free from its official website).
2. Use AOMEI Partition Assistant to create a bootable media (USB, CD/DVD).
3. Insert the bootable device you created before to the computer that its MBR is damaged or corrupted, and boot the computer from the bootable media. It Will get into AOMEI Partition Assistant automatically.
Step 1. Right-click the disk which need to be repaired and select “Rebuild MBR” in the pop-up window.
Step 2. In the next window, set the type of MBR for the current OS. (Choose a proper MBR type according to your operating system.) Then, click “OK” to continue.
Step 3. After that, click “Apply” on the toolbar to commit Rebuild MBR operation.
After finish this operation, unplug the bootable media and restart computer.
“Rebuild MBR” is a lossless data operation, but improperly rebuild MBR may cause your computer unbootable. So, you’d better learn more relevant knowledge before you do this operation.
“Rebuild MBR” only can solve problems such as corruption of the MBR code. It cannot solve the problem that the operating system cannot be booted due to the loss of bootable file or system file.
Follow these simple steps, you can easily and effectively repair your damaged MBR without losing data. Free AOMEI Partition Assistant is such a powerful MBR repair tool. Besides repair MBR, it also has many other powerful features, such as resize partition, move/create/delete/format partition, migrate OS to SSD, convert data disk between MBR and GPT partition styles, NTFS to FAT32 converter and so on. If you want to convert dynamic disk to basic or change partition type ID, you can upgrade to AOMEI Partition Assistant Professional.