Tuesday, 3 November 2009

Repair MBR for Windows 7 installed on MacBook

A couple of days back, I installed Ubuntu Karmic (Ubuntu 9.10) on my MacBook to give me a triple OS boot option (which I will write about in another post). My MacBook also had Windows 7 Home Premium Edition installed previously. During the installation, I selected Ubuntu to write the Grub onto a separately created partition (formatted to FAT32) under the Advanced Installation option. Following the installation, I found that the Windows 7 MBR (Master Boot Record) was overwritten by GRUB (Grand Unified Boot Loader). As a result I got a message "Missing Operating System" when I started Windows 7. This is how to get it back.

(Caution: This tutorial is only for restoring MBR on Windows 7. Do not use this tutorial if you are unsure for whatever reason).

Step 1: Insert the original Windows 7 DVD. (For Mac users, press the Alt (or Option) Key and hold until you see the DVD symbol and choose it).

Step 2: Choose the suitable Language, Time and Keyboard.

Step 3: Press Next and choose the option Repair your Computer. Do not press Install Now.

Step 4: Select the Windows 7 Installation and press Next.

Step 5: You will be presented with five options; (1) Startup Repair, (2) System Restore, (3) Windows Complete PC Restore, (4) Windows Memory Diagnostic Tool and (5) Command Prompt. Select the fifth option.

Step 6: You will end up at something like this X:\>Sources. Get set to enter some DOS commands.

Step 7: Type the command "cd.." (without quotes). This will take you to the root directory X:\>.

Step 8: Type the command "cd boot" (without quotes). This will take you to the boot directory, which should look like this X:\>boot.

Step 9: Type the final command "bootsect /nt60 C:" (once again without quotes). This would have restored your MBR to its previous state.

Step 10: Eject the DVD and press Ctrl-Alt-Del for PC users. For Mac users do a Hard Reset (by pressing power button and holding it until it shuts down).

Your MBR would have been restored. I did this on a MacBook and it worked.

5 comments:

Alex said...

Thanks, this helped when playing with Lucid Install on new macbook.

arthur said...

please i need help!!! the command prompt cd boot comes back "the system cannot find the path specified" i dont know what to do now. ive gotten so far with your help and have now hit a brick wall

Derrick said...

Yes there is no boot directory. I still typed the command it seemed to get rid of the grub loader but now I just get flashing cursor top left of the screen and nothing else!.

Anonomous said...

Help it is stuck at starting windows

tonwin said...

Your continued help and very useful.