Mac Pro Freezing

I am using Logic Pro X (Full) on my 2014 Mac Pro

Whenever I carry out simple audio editing in the arrange window such as drag out the file, cut/paste, move it around etc my whole system freezes. The track will still play, I have control over the mouse (cable) yet I cannot do anything else other than reach for the on/off button and turn it off.

I cannot access Force Quit or any other applications across either the toolbar or the header.

I am running Logic X with a MOTU Ultralite (Audio) and Micro Lite (Midi) I am using a 2007 Apple Cinema HD monitor, AMD FirePro D300 2048 MB graphics and 32GB of RAM

Anybody else had this problem and if so how did you resolve it?

Cheers

Tim