I have made a clone of my HD onto my external which has been formatted with GUID but icannot seem to make it boot. whenever i try it just shows the folder with the ? mark in it. i have searched and found nothing helpful. does anybody have any ideas? thanks
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Can't OSX boot from external usb?
- Thread starter majorp
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I'm no expert, but I think that means an OS X file is corrupt. Try a reinstall first. Maybe its just a glitch.
Probably a corrupt file, but out of curiosity what kind of drive are you trying to boot from? Firewire or USB?
Edit: I feel stupid. I could have read what kind of drive you had in your title. As gauchogolfer said below, you can't use USB to boot from.
Edit: I feel stupid. I could have read what kind of drive you had in your title. As gauchogolfer said below, you can't use USB to boot from.
PPC Macs can boot from external firewire drives, but not usb ones.
This was one of the reasons people were upset they dropped fw support from new ipods.
Cheers
Edit: updated to reflect the discovery that Intel macs can boot from usb drives.
This was one of the reasons people were upset they dropped fw support from new ipods.
Cheers
Edit: updated to reflect the discovery that Intel macs can boot from usb drives.
I've made a bootable backup of my internal using SuperDuper! onto my external USB2 drive. That shows up in the StartupDisk.prefPane on my MacBook (though I haven't actually tried booting from it).
I also used to be able to boot from a USB1 drive with my Pismo...
I also used to be able to boot from a USB1 drive with my Pismo...
I was under the impression that Intel Macs can boot from USB, but I might be wrong. I am wrong so very often these days.
mad jew said:I was under the impression that Intel Macs can boot from USB, but I might be wrong. I am wrong so very often these days.
No, you can't. I think it has to do with how USB isn't as stable bandwidth wise as FireWire. I'm sure the real explanation is much more technical
PPC macs cant boot from USB2 but Intel macs work just fine. I have a 250GB external HD that I occasionally boot from.
I've heard lots of reports that you can boot from USB drives on Intel Macs. I've only done it on Firewire drives, but I have a small USB external drive at home that I'm not using any more. I'll try it out tonight and give a definitive report later.
Edit: Actually, my external firewire drive here, which has OS X installed on it as a backup, is dual firewire/usb. Give me a few minutes and I'll swap over the cables and reboot.
Edit2: Boots no problem using USB. It's noticeably slower to boot, I didn't time it though, but it's usable. I'll try the other drive later or at the weekend, whenever I can get time, and try it. One thing to note is, it's not a clone of my drive, it's a separate install of OS X.
Edit: Actually, my external firewire drive here, which has OS X installed on it as a backup, is dual firewire/usb. Give me a few minutes and I'll swap over the cables and reboot.
Edit2: Boots no problem using USB. It's noticeably slower to boot, I didn't time it though, but it's usable. I'll try the other drive later or at the weekend, whenever I can get time, and try it. One thing to note is, it's not a clone of my drive, it's a separate install of OS X.
Yeah, most likely corrupt. Maybe try installing OSX freshly onto the external and then booting from it. That way you can work out whether it's a problem with the data or with the enclosure/drive/cable that's preventing you from booting at the moment.