My Book Studio for Mac USB 3.0 not bootable

WD External Drives External Drives for Mac
1

Hello, I have a My Book Studio 3TB USB 3.0 drive I am using with my Macbook Pro and Mountain Lion.  In System Preference, I am able to specify the drive as a Start-up disk and it works fine.

However, when booting to Startup Manager (by pressing the Option Key at Startup), my My Book Studio does not show-up.  Does anyone have any advice on how I can get the drive to show-up as a bootable option?

Thanks

2

This article should be useful for you:

List of Mac-bootable WD external drives and how to format them to install an operation system

http://wdc.custhelp.com/app/answers/detail/a_id/1787

3

use disk utilities to reformat drive to apple and it will work fine

4

Thanks for the suggestion.  I tried that, but it still does not work. 

5

chrisfound wrote:

use disk utilities to reformat drive to apple and it will work fine

That depends on the processor. APM is for old PPC Macs while Intel Macs MUST use GUID, even Disk Utility informs you so.

6

I have an Intel Macbook Pro Retina 15" and the drive is formatted to GUID.  I bought the silver Mac edition, but I also tried reformatting to with GUID.  It sitll does not show up under Startup Manager.  However, it does allow me to select it as a startup disk in System Preferences, and that works fine.  Any ideas?