I just wanna share my solution regarding the issue of the “No Preview”. Recently, I had a struggle to find the solution because my AE CC 2018 has no Monitor and it was really a mess not seeing what’s going on with my COMP. Now it’s working fine. I just downloaded the update for my NVIDIA Graphic Card for Windows 10. Basically, I never thought that the solution would be just to update the driver. Because when I checked on the Device Manager, my Graphic Card is working fine until I tried looking for a new update for the NVIDIA GC. Cheers!