Wavelab 12 crashing when using external hardware

Wavelab seems to keep crashing whenever I use the external FX in my chain. I just have 1 hardware device hooked up which I’m running audio through. It’s now crashing everytime, as soon as I hit render I get the Apple wheel and Wavelab is unresponsive. If I then force quit Wavelab, reload the same chain, it works again. Can anyone help me out with some solutions?
Thanks!

Give a try with a simple setup with just the External FX in the Master Section.

Thanks for your reply, I have tried this and the first time it worked, 2nd time it crashed again.

Then provide a crash log.