I have Adobe Captivate 2019, version 188.8.131.526. I have a mac and I use Chrome as my default. I am no longer able to preview my projects and I am getting an error that says "cannot open project." This is a new issue for me and consistent across all projects that I open. I haven't changed any settings and have never had this issue.
As a Win user I am unable to help you really. Just want to ask if you recently updated your OS?
I haven't updated for a long time.
Sure about silent updates which happen every Tuesday?