Canon 550D - Manual (Page 222)

Troubleshooting Guide
222
If the LCD monitor is dirty, use a soft cloth to clean it.
In low or high temperatures, the LCD monitor display may seem slow
or might look black. It will return to normal at room temperature.
In Basic Zone modes and in movie shooting mode, certain tabs and
menu options are not displayed. Set the shooting mode to a Creative
Zone mode (p.40).
If the image has been protected, it cannot be erased (p.170).
Set the color space to sRGB. If Adobe RGB is set, the first character
will be an underscore (p.96).
If you use a card which already has images recorded, the file
numbering might start from the last image in the card (p.140).
Display & Operation Problems
The LCD monitor does not display a clear image.
The menu screen shows few tabs and options.
The image cannot be erased.
The file name’s first character is an underscore (“_MG_”).
The file numbering does not start from 0001.