RogerS wrote on 7/10/2020, 2:43 AM

You don't state what version of Vegas Pro you are using. VP 17 452? Update your version of Vegas to the most released update.
You don't state what graphics driver you are using either. Try the latest NVIDIA studio driver to start with.

If that doesn't resolve your issue, read this post for more info you need to share so we have some chance of figuring out what's wrong: