Thank you both.
Yes I do have GPU turned on. From what I gather from you Steve, this won’t help though. I will give it a try nevertheless.
I will try the close/restart Vegas and report back. It’s currently happening on a project. It’s very inconvenient though as I cant get a clear preview of what my work looks like. I even tried a RAM preview of a troublesome section… problem appeared there as well.
PS. my apologies for using the term “clip” erroneously in previous posts. I meant to say “event”. Good catch.
Gilles