Canon 5D MK III User Manual (en)

Operation of the auto power off function will automatically switch the 
camera off, disabling communication with EU, if you turn the auto 
power off function to [ON]. Remove the check mark from [Auto power 
off] in the preferences ([Basic Settings] window) 
 or set the auto 
power off function in the camera to [OFF].
If you do not perform any operation while the camera and computer 
are connected, depending on the computer system, a confirmation 
message may appear on the screen asking whether you wish to 
continue communicating with the camera. If you do not perform an 
operation while this message appears, communication with your 
camera is discontinued and EU shuts down. In this case, turn the 
camera’s power switch to < OFF >, then again to < ON > and start up 
Do not put your computer to sleep while it is connected to the camera. 
If your computer goes into sleep mode, never disconnect the interface 
cable while your computer is still in sleep mode. Always wake your 
computer up while it is still connected to the camera. Depending on 
the type of computer, disconnecting the interface cable while your 
computer is in sleep mode could prevent the computer from waking 
up correctly. Refer to the computer User’s Manual for more 
information on sleep mode.
When a non-Canon flash is mounted on the camera for Remote Live 
View shooting, set [Silent shooting] in the camera to [Disable].
Communication between EU and the camera disconnected
A non-Canon flash does not fire during Remote Live View shooting
In Digital Photo Professional, select the [Tools] menu  [Sync folder 
with EOS Utility].
Remotely shot images using EU are not displayed in DPP