See an icon on your iPod and don't know what it means or what you should do? I have included links to the Apple KnowledgeBase Articles if you need more info. N.B. Some icons remain black and white even on an iPod with a color display.
This mainly happens when the battery needs to be recharged. Connect iPod to the power adapter to charge it. You can probably also charge it by connecting it to your computer. If you have tried recharging and iPod still shows this icon, then see HT1384 Charging your iPod battery for more steps to try. Newer iPod models may instead say "No Battery remains. Please connect iPod to power".
Monochrome low battery
For some iPod models, if your battery has been fully or nearly discharged, a monochrome non-animated version of the battery icon, shown above, appears on the screen when connected to your computer's USB port (even with a color display). In this state, the iPod will not be able to communicate with your computer. Simply leave the iPod connected; when the iPod is sufficiently charged it will turn on enabling you to sync it with iTunes. For more information see HT1435 About the battery charge status icon.
This also relates to the diagnostic software noted above. The icon means that the disk scan was not able to recover the hard disk data. When this happens, try the steps in TS1373 iPod displays a sad iPod icon first.
Apple logo
The Apple logo normally appears briefly when iPod is reset or turned on after being off for several days. If the logo does not go away after being charged, see TS1399 iPod only shows an Apple logo and doesn't start up for steps to take.
Do not disconnect
The "Do not disconnect" message appears when iPod is configured to manage songs manually. See HT1853 Safely disconnect iPod for steps on how to disconnect it without losing data.
Power adapter plugging into wall
This icon appears on the screen during an update or restore that occurs when iPod is connected to the computer via a low or no-power connector. This can include some USB ports and 4-pin FireWire ports. When this appears, disconnect iPod from the computer and connect it to the power adapter. Then plug the power adapter into a power outlet. The update or restore will complete and iPod will restart to the main menu.
Disk platter icon with a magnifying glass (or disk icon with exclamation point, checkmark, "x", or arrow)
These icons all relate to built-in diagnostic software that checks the hard disk for damage and tries to repair it if necessary. The checkmark indicates all is well with your iPod. See TS1891 Disk Scan Icon appears when iPod is turned on to find out what the other icons mean and what you can do.
