Why won't my usb key boot my macs?

July 13, 2010 8:40 AM

We have a macbookpro with a touchy DVD drive. I'm trying to upgrade it to snow leopard, but I somehow can't get my usb drive to be bootable.

I made an image of the snow leopard dvd (confirmed good by MD5 & google) on my macbook, which is already running snow leopard. Using disk utility, I've restored this image onto a PNY-brand 8GB usb drive, after first partitioning the USB drive Mac OS Extended (Journaled), GUID.

Everything appears to work fine each time, and the resultant disk looks just fine as a snow leopard disk. But neither the MBP or the MB will ever boot off it, or even recognize it as a bootable drive. What might this be? Do I just have a weird usb drive (I don't have another to try, though I guess I can buy one)? Or am I missing something obvious?

posted by kickingtheground to computers & internet (6 answers total)

Make sure that when you're trying to boot off this drive, you hold down the Option key immediately when you power on the computer with the drive plugged in. You should get a choice of start-up disks and the flash drive should be one of them if you extracted it right.

To create the image, you'll want to use Disk Utility and create a master. Then wipe and delete any partitions off the flash drive and then "Restore" it with that image you created.

Also, if for some reason this still ends up being a pain, remember that both of these machines supports Remote Disc, so you can leave the install disc for OS X in the MacBook you have and boot against that image as long as their on the same network. See Apple's KB article for help with Remote Disc here.
posted by cgomez at 8:47 AM on July 13, 2010

Regardling remote disc mode - appears not.
(I should have mentioned, the MBP is still running tiger.)
posted by kickingtheground at 9:02 AM on July 13, 2010

What I've had to do on some laptops in the past is fire it up just so the disc spins up, then immediately reboot it and get to the boot menu.
posted by jjb at 10:07 AM on July 13, 2010

Last time I went through these hoops it turned out that the build version of OS X was the issue.

I had to make sure I was using the Startup DVD that shipped with my unit (27" iMac) and not just a factory install disk. The entire saga is outlined here.

Henry
posted by silsurf at 6:06 AM on July 14, 2010

Did you partition it with GUID? I suspect you need to.
posted by chairface at 2:03 PM on July 15, 2010

Ended up just being a flaky usb drive. Switching to another sandisk drive fixed the problem.
posted by kickingtheground at 11:02 AM on July 21, 2010