Post by Tom Evans
Is it important to shut down -- or log out from --a Mac desktop
computer before attaching an exteral drive?
There's normally no need to shutdown or log out. Sometimes you may need
to if the drive having issues and won't dismount any other way.
To normally dismount a drive you simply eject it from the OS. There are
various ways to do that, including:
- Click on the drive's desktop icon and choose Eject
from the Finder's File menu (or press Command E).
- Click on the small eject symbol next to the drive's
name in the sidebar of any Finder window. (Note: This
symbol can be a bit flakey, so may not be there.)
- Click on the drive's desktop icon and press the Eject
key on your keyboard (if applicable) - usually F12, but
may need to hold down one of the modifier keys depending
on how your Function keys are set-up to work.
- Drag the drive's desktop icon to the Trash in the Dock
which will change to an Eject symbol (this only ejects
the drive, it doesn't not erase it or delete anything).
Check the Finder's Preferences are set to show external drive icons on
the Desktop or the sidebar.
Whichever method you choose, the OS will dismount the drive as long as
it's not still being used by an application, saving any unsaved data
and closing files, and you can unplug it once its icon disappears from
the Desktop / Finder window sidebar and the activity lights on the
drive itself go out (if there aren't any lights, such as many USB
keyring drives, then just wait a couple more seconds).
Note: There is one exception to this when using vintage / obsolete
Macs and external SCSI devices. You aren't meant to turn on
or off SCSI devices when the computer is running (even after
ejecting the disk / drive) ... although having said that I
never had any problems whenever I did it.