You start the computer and an icon that looks like a spinning globe appears. After awhile, a question mark replaces the globe and finally the computer boots normally.
The computer has been set to start from a network. This is indicated by the globe. The computer searches for a network volume but can't find it so it displays a question mark to indicate that it is confused. After looking around for a bit, the computer finds the first volume that has a valid system and boots from it.
The solution is to open
System Preferences, select the
Startup Disk preference pane (which will say
"Select the system you want to use to start up your computer") and re-select the desired startup disk. Then, restart to test.
If you are already shut down and want to expedite the boot process, press and hold
Option during startup. Release the key when you see a choice of startup disks, select your desired startup volume (likely to be either a hard drive or a partition of a hard drive) and press
Return.
For more information, read
Mac OS: Flashing Globe When Computer Turns On Written by jchuzi with contributions from artie505, dianne, dkmarsh and joemikeb in Selecting desired startup volume or drive.
(Note: you must be logged in to read the development thread.)
