Canon EOS 7D Instruction Manual page 248

Troubleshooting Guide
Part of the image blinks in black.
The [4 Highlight alert] menu option is set to [Enable] (p.163).
A red box is displayed on the image.
The [4 AF point disp.] menu option is set to [Enable] (p.163).
The file name's first character is an underscore ("_MG_").
Set the color space to sRGB. If Adobe RGB is set, the first character
will be an underscore (p.82).
The file numbering does not start from 0001.
If you use a card which already has images recorded, the file
numbering might start from the last image in the card (p.80).
The shooting date and time displayed is incorrect.
The correct date and time has not been set (p.42).
No image appears on the TV screen.
Make sure the AV cable or HDMI cable's plug is connected all the way
in (p.176, 177).
Set the video OUT format (NTSC/PAL) to the same video format as
the TV (p.240).
Use the AV cable that came with the camera (p.176).
Printing-Related Problems
There are fewer printing effects than listed in the instruction manual.
What the screen displays may differ depending on the printer. This
instruction manual lists all the printing effects available (p.194).
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