Why do I need to press the shutter twice?

[Arbutus]

In any non-auto mode (P/T/A/M) i need to press the shetter button twice - one seems to raise the mirror, judging by the noise; the second press takes the picture correctly at the speed&aperture set. But clearly this is not right.

In any of the auto modes - A+ etc,  one press takes the picture.

I have reset the camera (T4i) to factory default settings.

I use only Canon lenses. AF or MF mode makes no difference. All lenses cause the same symptoms.

Is there a setting I am missing here?

Any help very much appreciated!!!!

[TTMartin]

Sounds like you have mirror lock up turned on.

There are two places to reset the cameras settings.

One is clear custom functions and the second is clear camera settings. 

Be sure you have fully reset your camera to its defaults.

[Arbutus]

Ahhh  !    I knew there was a setting somewhare.  It is under Wrench4:Custom Functions  Page5 MIRROR LOCKUP

Thank you !!!!