Repairing GRUB

Well, my PowerPoint – actually LibreOffice Impress – presentation on the basics of Ubuntu Linux, given to members of the Ottawa PC Users’ Group a few days ago, went quite well. Unfortunately, the same cannot be said for the live demonstration of installing Ubuntu!

I had set up my laptop’s hard drive as a single partition with Windows Vista installed. To demonstrate just how simple it is to install and use Ubuntu, I used a USB memory stick on which I had installed a bootable version of the Ubuntu 11.10 distro (using UNetBootin). It was easy enough to show how to start up the “live-CD” version of Oneiric Ocelot, and then navigate through the few setup screens in order to commence the process to install Ubuntu to the hard disk. I chose to establish a dual-boot format with Vista, and then left the software to run while I gave my main presentation on a second computer.

Finally, at the end of the presentation, the pièce de résistance – restart the laptop and demonstrate how easy it is to boot into – Windows!? Yes, that’s right, the demo-gods were not smiling on me that evening – or perhaps they were! After a re-boot, the laptop failed to show the GRUB start-up menu, and booted directly into Vista.

A quick check using GParted from the bootable USB stick confirmed that the Ubuntu root and swap partitions had been created, as had the /boot/grub folder, and there was a reasonably-configured grub.cfg file. Clearly, the problem was that the installation had somehow failed to reset Vista’s master boot record (MBR) to point at GRUB.

So, how to fix this little mishap? Once back at home, I tried my bootable Super Grub Rescue CD. Now, perhaps I have an old version of this software, but the only option that Super Grub Rescue provided was to boot into the installed Linux system. While this let me use Ubuntu, and so confirmed that the installation was viable, it wasn’t going to fix the boot problem.

I decided it was time to learn more about just how GRUB works, and how to manually fix boot problems. However, a Google search identified an Ubuntu Community document discussing the use of Boot-Repair as “a small graphical tool to restore access to Ubuntu.” Even better, Boot-Repair offered a “Recommended repair button to repair most frequent boot problems. (generally repair filesystems and reinstall Grub2).”

This sounded like just what I needed. So, out with the idea of learning about the inner-workings of GRUB, and move along to try yet another boot-fixing tool.

Downloading and installing Boot-Repair was as simple as following the instructions in the Ubuntu Community document. Copy each of two commands that were provided and paste them into a Terminal window (recalling that one needs to use Ctrl-Shift-V as the keyboard short cut for pasting), and let each command work its magic.

In no time, I had the main Boot-Repair window on the screen. Sure enough, the “Recommended repair” button promised that it “repairs the most frequent problems”. Pressing this button, and waiting patiently while it did whatever repairs were indeed recommended, led to a request to restart the computer.

Now, the GRUB menu was immediately displayed, and the laptop would into boot into either Ubuntu or Windows Vista.

In addition, to the “quick repair” button, the Advanced Options for Boot-Repair allow considerable customization of the utility’s operations, including backing up partitions, boot sectors and logs; repairing file systems; changing the location of the boot flag; restoring the MBR; and editing GRUB’s configuration file.

Alternatively, the program offers a second button to run Boot-Info-Script, a trouble-shooting utility that will produce a very useful list of all the hard drives installed in the computer and information related to the boot-up process.

So, if you need to fix a boot problem, Boot-Repair may well be worth a try. And even if you want just a little more information about your system’s hard drives, this little utility can provide the goods.



Boot-Repair, simple tool to recover access to your Operating Systems

UNetbootin – Homepage and Downloads

Super Grub Rescue

Boot Info Script


This entry was posted in Applications, GRUB. Bookmark the permalink.

3 Responses to Repairing GRUB

  1. suraj mokal says:

    My os is ubuntu.14.04….
    When i start my pc the message shows up …..
    grub rescue>
    and do all settings then message shows up
    Error: attemt to read or write outside of disk ‘hd0’
    Please help me for solving the prob.

  2. Pingback: Ubuntu:Grub rescue prompt, repair grub [duplicate] – Ubuntu Linux Questions

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