you're absolutely rightRod Rod said:After repairing disk permissions I log out and then log back in to make sure nothing's running . . . it's a bit easier than analyzing Activity Monitor processes. And of course I eject, switch off and unplug (the FW cables of) all FireWire devices.
I'd recommend to unplug all devices USB included
and I'd recommend for laptops to plug in computer to the power
outlet to make sure that installation won't be interrupted if something will be wrong with computer's battery