Canon EOS-1D C - Manual (Page 356)

356
w: Registering Custom Shooting Modes
My Menu settings will not be registered.
When the shooting mode is 1>, 2>, or 3>, you cannot select
[54: Clear all camera settings] and [87: Clear all Custom Func.
(C.Fn)].
Even in the 1>, 2>, or 3> shooting mode, you can still change
the shooting function settings and menu settings.
displayed on the top LCD panel together with the shooting mode
indicates that a registered Custom shooting mode is in use.
COP
Y