Various icons on the Apple iPod stand for folders, battery, loss of data, power adapter and disc, according to Apple's official iPod iconology page. Symbols appear when functions occur on the device. Some of these icons mean users should do something while others signify normal operations.
Apple's iPods have standard symbols that indicate the same thing across several versions of the music player. A folder with an exclamation point means the device may need to be reformatted and should be connected to a computer. The folder and exclamation point symbol also signifies the software needs to be updated.
When the battery needs to be recharged, an icon with a battery and exclamation point appears. A monochrome battery symbol appears on some models; when this happens, an iPod will not communicate with a computer. A folder with an exclamation point may also signify a battery issue.
A sad iPod logo relates to diagnostic software. A "do not disconnect" message with a red circle and line through it indicates the iPod is configured to manage songs manually. A disc icon means some kind of diagnostic is running on the player. These diagnostic programs attempt to fix hard drive damage. StreetDirectory.com states if the iPod is under warranty, some software problems can be fixed by the manufacturer.