2009
Repair a Non-booting Mac after Linux Install
While at NSCoder Schaumburg last night I installed Ubuntu 9.10 to a USB stick attached to my MacBook Pro. I mistakenly didn’t check the bootloader installation settings, as I thought it was safe since I was installing to the USB stick. That was a bad idea, because I rebooted to a find the dreaded Question Mark Folder on my screen.
This basically means the system can’t find a disk to boot from. In this case, Ubuntu removed the expected EFI boot code and replaced it with their own code. My data was all there, just the drive wasn’t bootable. Also since I wasn’t at home I had no boot disk on hand to fix the problem. Luckily fellow NSCoder Kevin Mitchell had his Mac OS X Snow Leopard disk with him.
I figured it would be fixed with a simple “Disk Repair” command in Disk Utility, or a simple command line to restore the boot code to normal. But after trying various methods to repair the system, I was getting no where. I was worried I’d have to re-image the drive once I got home. So I started to Google around as I knew a solution had to be out there. I eventually found this article on macosxhints.com that had a simple solution that worked flawlessly! A simple resizing of the Mac’s HFS partition will reset the EFI boot code.
Run Disk Utility and click on your internal hard disk (the disk itself, not the partition under it).
Then click on the Partition tab. If you move the triangular slider that adjusts the partition up and then back to where it was, the “Apply” button becomes active (it starts greyed out).
You can now click “Apply,” and the partition will be left alone, but the bootloader will be recreated.
This tip saved the day for me, so I figured I’d share it. As I hope it is a tip that someone can use in the future themselves.
