Troubleshooting Startup Problems Before Finder/System Hangs During Boot - 40
External device is bad. Disconnect all external devices (USB and Ethernet). Then
begin reconnecting these devices one at a time (beginning
with the keyboard and then the mouse) and start up the
computer after each device is connected to see if one of
the external devices is causing the problem. If the
problem occurs after you connect a particular external
device, replace the device in question.
This problem refers to a system that begins a normal startup process with a boot
chime and normal display, but then freezes before the Finder appears.
Possible Cause Possible Fix