My bad re comments on previous posts, they are here http://www.heliconsoft.com/forum/viewto ... =12&t=2207

The mirror lock up mode is not being detected on my Canon 1D Mark IV with 2.4.4w (downloaded this morning)
I rebooted after install and closed all other programs.
I just submitted a bug via the software bug report tool.
If it helps on the 1D Mark IV mirror lock up is set via custom function group ...