Canon EOS 5D Mark III Instruction Manual (en)

Troubleshooting Guide
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 may look black. It will return to normal at room temperature.
[Eye-Fi settings] will appear only when an Eye-Fi card is inserted into 
the camera. If the Eye-Fi card has a write-protect switch set to the 
LOCK position, you will not be able to check the card’s connection 
status or disable Eye-Fi card transmission (p.350).
[33: Highlight alert] is set to [Enable] (p.253).
[33: AF point disp.] is set to [Enable] (p.253).
If the image is protected, it cannot be erased (p.278).
Movies edited with a personal computer cannot be played with the 
If you operate the camera’s dials or lens during movie shooting, the 
operation noise will also be recorded. Using the Directional Stereo 
Microphone DM-E1 (sold separately) is recommended (p.237).
The LCD monitor does not display a clear image.
[Eye-Fi settings] does not appear.
Playback Problems
Part of the image blinks in black.
A red box is displayed on the image.
The image cannot be erased.
The movie cannot play.
When the movie is played, camera operation noise can be heard.