How to Fix MBR in Server 2012 (R2) Easily

Corrupted MBR on Windows Server 2012 (R2)

The Master Boot Record (MBR) is the first place the system BIOS tries to access when you power up a machine. The code stored there then searches the drive for an active partition. Next, the system locates the boot sector and begins executing the file that the boot sector pointed to, after which it moves onto the NT Loader (Ntldr).

If your Windows Server 2012 R2 doesn’t boot, one of the possible causes is an error or corrupted file in the first stage of the boot process. These can be caused by a number of different reasons such as a bad boot sector, virus infection, a hacker etc. Typically you will receive one of the following error messages: Corrupted MBR, Invalid partition table, Error loading operating system, or Missing operating system.

These errors are not restricted to Windows Server 2012 R2 and can effect Windows Server 2025, 2022, 2019, 2016. The below guide will inform you how to repair the MBR error in Server 2012 (R2).

Two ways to effectively fix an MBR error in Server 2012

The Windows Server operating system actually provides an inbuilt way to resolve MBR issues. You can repair an MBR error with the help of the Recovery Console found in the Windows installation disc.

Repair a corrupted MBR in Server 2012 via the Recovery Console

Insert the installation CD to your machine. Boot the system from the CD by changing boot order in the BIOS.

1. Insert the installation CD to your machine. Boot the system from the CD by changing boot order in the BIOS.

2. Select Recovery Console option when prompted.

3. Go to C:WINNT or C:\WINDOWS. You may need to enter the local administrator’s password in this step.

4. In the Command Prompt window, type fixmbr and press Enter. You should confirm that you want to proceed by typing Y and then pressing Enter.

5. Remove the CD and boot as normal from the hard disk.

Notes:✎...

If there is an issue with the boot sector, type: FIXBOOT.

If you have more than one copy of Windows please make sure you are using the correct one.

It is very simple to fix an MBR error with the help of the Windows installation CD. However, what can you do if you don’t have the correct Windows installation disk to hand? If this is the case, we recommend using some professional tools as a workaround.

Rebuilding MBR for Server 2012 the easier way

AOMEI Partition Assistant Server Edition is a comprehensive hard drive partition manager that is specifically designed for Windows Server OS’s. With this specialist software, you can easily rebuild the MBR table for the Server operating system. When the machine is not bootable you can utilise the "Make Bootable Media" function to ensure that you can always fix your Server.

Preparations:✎...

A USB flash drive (or CD/DVD disc) to make a bootable media device.

A machine to complete the creation of the bootable media device. AOMEI Partition Assistant Server Edition needs to be installed on this machine.

1. Plug the USB drive to your computer, and install and launch AOMEI Partition Assistant Server Edition. Click on Make Bootable Media  in “Tools” in the top toolbar and follow the wizard to complete the process. Specific drivers for Server 2012 can be added during this process.

2. Set your Server 2012 to boot from the created bootable device by changing the boot order in the BIOS.

3. Once logged in, you’ll see that AOMEI Partition Assistant Server Edition has started automatically. Next, find the disk that has a corrupted MBR table, right click it, and select Rebuild MBR.

4. Choose the correct type of MBR table for your Windows Server 2012 in the pop-up box. In this case, you should choose the "Windows 7/8/10/2011/2012" option.

5. Click Apply and then Proceed to execute the change. Now, wait for the process to be completed.

6. Disconnect the bootable device and restart your Server.

Notes:✎...

The above steps can also be applied to fix the MBR other versions. You should remember to choose the correct MBR type for your system.

You can run CHKDSK in elevated mode after you have completed all of the steps to see if there are any other errors on your disk.

Other tips if Windows Server 2012 is not booting

If the boot problem is not caused by a corrupted MBR, you can try repairing the Server 2012 (R2) boot files.

1. Boot from the installation disc and choose Repair your computer in the lower left hand corner. Next, open a Command Prompt window via the Advanced option.

2. You can run a system files check and use the offline options in the prompt.

▪ SFC /OFFBOOTDIR (for offline repair specify the location of the offline boot directory)

▪ SFC /OFFWINDIR (for offline repair specify the location of the offline Windows directory)

3. Remove the CD and reboot the computer.

Next steps: If you have discovered that there is a problem with the Boot Configuration Data (BCD) store, you may want to refer to this guide: Windows Server 2012 boot BCD error.

Verdict

Here we introduced two reliable ways to fix the MBR table in Windows Server 2012. You should choose the most suitable method according to your own situation and circumstances. In case anything goes wrong in the future we recommend backing up your Server 2012 on a regular basis.

AOMEI Partition Assistant Server Edition is the perfect specialist tool for any Windows Server issues that you may encounter. It even includes such great features as the ability to convert an MBR table to a GPT one without data loss in Windows Server 2012, regardless of how the disk is being used (system disk or data disk).

To enjoy those amazing disk management functions on unlimited Servers/PCs within one company with only one license, you can try AOMEI Partition Assistant Unlimited. And the Unlimited Edition has "Create Portable Version" function, which allows you to create AOMEI Partition Assistant to a removable device.