How to Repair Windows Dual Boot, Multi-boot?

Dennis Faas's picture

Infopackets Reader 'Sprenger' writes:

" Dear Dennis,

I have four hard drives in my PC and four different operating systems. My main hard drive has Windows XP, then my second drive has Vista Ultimate, the third has Windows 7 Ultimate, and the fourth has Windows 8.1. I want to get rid of the Windows XP drive, but if I disconnect it, none of my other hard drives will boot. What should I do? I prefer to have Windows 7 as the default operating system. I want to avoid formatting all my hard drives just to get them working again. Any suggestions? "

My Response:

It sounds like your Windows XP drive holds the master boot record (MBR), along with all your boot options and list of operating systems. If you remove it from your system, there is no longer a hard drive to boot from, nor will you be able to boot the other drives as they rely on the Windows XP hard drive for the initial boot.

There is an easy fix to get each of the drives booting again independently. Once that's done, you can use third-party utilities to re-establish the multi-boot.

How to Repair the Windows Master Boot Record (MBR)

To make your Windows 7 hard drive bootable, do the following:

1. Shut down your system and unplug the power

2. Disconnect all hard drives except the Windows 7 drive

3. Insert the Windows 7 install media (DVD) and boot from that

4. Select the 'Repair Your Computer' option (near the bottom of install screen) instead of the option to 'Install now'

5. Follow the on screen instructions to have Windows 7 scan your system. It should find your Windows 7 hard drive and fix the MBR automatically for you

6. When complete, eject Windows 7 DVD; reset the computer, and try booting your Windows 7 hard drive

Repeat the same procedure as above for the Windows 8.1 hard drive, substituting the word "Windows 7" for "Windows 8.1". The procedure for Windows Vista is similar, but requires manually entering commands via the command prompt. Refer to this post on how to repair Windows Vista MBR.

How to Repair Windows Dual Boot / Multi-boot Menu

Once that's done, it's time to re-instate your multi boot menu on the Windows 7 drive. This procedure is rather technical and prone to error; as such I'm going to recommend using third-party utilities to re-establish the multi-boot. Here are the steps:

1. Shut down your system and unplug the power

2. Re-attach all the hard drives to the system

3. Power on the system and enter the BIOS

4. Modify the BIOS boot options and set the Windows 7 drive as your default boot drive

5. Save your settings and exit the BIOS

6. Boot from Windows 7

Following that, use one of the dual boot / multi-boot utilities mentioned below.

EasyBCD (free for non-commercial use, but it has limited features):

Dual Boot Repair by Bo Yans:

If anyone knows of similar programs that can easily repair a multi-boot / dual boot, please chime in with your suggestions.

About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

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nate04pa's picture

When I clicked on "Online Help", Malwarebytes flagged it. Not sure it wasn't a false positive.

gi7omy's picture

I multi-boot here (again four OSs - Windows XP, 7, 8.1 but I also use Linux. GRUB does the job by calling up the installed Windows boot manager on each disk so I can either boot via GRUB or select the drive I want to boot from (in BIOS).

There are other boot managers available (for windows) one example is GAG