no boot sector detected

[mindaugas]

I tried carbon copy cloning my OSX partition to a faster hdd and when I try to boot off it it says no boot sector detected. I know what that means for Windows, but how do I fix an OSX no boot sector? I tried disk util, but it didn't find any errors. I also tried selecting it as a startup disk.

[nendra]

[...] no boot sector detected [...]

 

Does it *really* says that ?

 

Check if your new disk is setup with a MBR (either fdisk -e or Disk Utility -> partitions -> options)

[mindaugas]

ya, it says that, even after re-partitioning and re-loading OS X, really weird. Another USB drive works fine though. how do I rebuild an OS X mbr tho?

 

and it is the only USB hdd attached to my laptop. Dell is telling me no boot sector, well, suppose that's obvious

[nendra]

how do I rebuild an OS X mbr tho?

 

boot in single user mode (-s) when you have the prompt do:

 

fdisk -e /dev/disk0s1

 

(replace disk0s1 accordingly to your setup of HDs and Partitions)

 

from there see the help, there should be something as fix mbr and set active partition (can't remember the switch right now) when you've finished, save your change with:

 

write

 

if that doesn't work you may need to go to Disk Utility and reformat your partition AND check in options that you've MBR checked. Then try a restore from your old disk.

 

 

good luck

[mindaugas]

no luck with any of that. I'm gonna load an image of Vista on and see if it will even boot. maybe my lappie won't boot a SATA --> USB2 drive for w/e reason, but does fine with IDE --> USB2. I repartitioned my internal drive and I'm gonna try and dual boot Vista/OS X off that. I would like to just have OS X on the external tho.

 

I fixed it, had to do this after botting single user mode from CD

 

fdisk -e /dev/rdisk1 (CD was 0)

flag 1 (only part on drive)

update

write

quit

reboot

 

except my stupid enclosure shuts the drive off after reboot, so I have to toggle power ... oh well, minor inconvenience for a faster external drive