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