How do i boot from usb?

[X1Lightning]

i used Carbon Copy Cloner to create a clone of my internal HD to an external usb hd, now if something happens and my internal drive gets corrupted how do i boot from the usb drive?

 

[drichards]

Hold option while booting, or alternatively, shift-command-option-delete.

 

[X1Lightning]

Thanks!!!

 

[Zortrium]

Does this actually work? I was under the impression that you could boot from an external firewire drive only, not a USB drive.

 

[jim.lynch]

I've done this from USB, it works fine.

 

[sickmacdoc]

Does this actually work? I was under the impression that you could boot from an external firewire drive only, not a USB drive.

The key to answering that is to ask whether or not you have an Intel based Mac. 😉

Intel machines will boot fine from USB drives, assuming they are formatted as Mac OS Extended (Journaled) and have been prepared with a GUID partition map. Intel machines will also boot from FireWire drives- but again with the correct format/partition map.

PowerPC Macs (although there are a couple of late model exceptions) will only boot from FireWire drives with a partition map type of APM (Apple Partition Map)- not GUID.

 

[dukebound85]

Does this actually work? I was under the impression that you could boot from an external firewire drive only, not a USB drive.

Yes, Ive installed osx from a flash drive. Tons faster than dvd