Disasater preview has stopped working (Resolved)

PLEASE HELP.

THIS PROBLEM HAS ME STOPPED COLD. ALREADY MISSED A CRITICAL DEADLINE.

It is suddenly is now impossible for me to switch back and forth between edit and preview mode.

What could be the cause of this problem?

First occurrence yesterday. Updated to 8.9.0 running under Mojave

Same problem.

Please see this thread:

This is exactly what I am seeing. I have found no way around this problem. That suggests a serious bug in the RW app.

Have you received any explanation from RW team?

They posted on the thread I sent you to.

?? Where do I find that, Adam.

I linked you to it here:

Dropped back to 8.3 and things stabilized.