Repairing Windows 7 MBR without installation media
Setting up my new work laptop with a dual boot system didn’t quite go as planned yesterday. In the middle of my Ubuntu install I came across the rather unhelpful error:
The installer encountered an unrecoverable error. The desktop session will now be run so that you may investigate the problem or try installing again.
Firing up my new Ubuntu install I’m greeted with half a filesystem and the not so promising error message:
/dev/mapper/ubuntu-root does not exist. Dropping to shell!
Looking into the partitions on my system I now had two new partitions at least:
sda1 SYSTEM_DRV sda2 WINDOWS7_OS sda3 LENOVO_RECOVERY sda5 swap sda6 ext4
Annoyingly, Grub treated the Lenovo system drive as a second Windows install, but I could live with that. I figured I’d get back into Windows, wipe the two new partitions and start again. Only this time I was met with the error a lot earlier in the process and Grub was dead, leaving me with no access to even my Windows 7 install.
error: unknown filesystem grub rescue >
Ah crap! Of course the only way to restore the Windows MBR is through the recovery console, which you can access through the install media — that doesn’t ship with laptops these days. Seriously, how much money does it cost to ship a damn DVD with a laptop these days?
Getting back into Windows was my biggest problem here. Using another system I downloaded the excellent, and incredibly easy to use, Super Grub2 Disc. Once back into Windows I was able to create a new System Repair Disc.
With this in place repairing the MBR was a piece of cake.