The computer running Connect Performer is a Mac laptop using 10.11.6 and there’s no second screen involved. Performer will launch but the application window is a blank white screen - no graphics whatsoever. All you can do is quit the application. We downloaded and re-installed a few times, with the same results.
Recently I had the same situation on my computer, 10.12.6, with another creator’s application. They instructed me to go to ~/Library/Application Support/Microsoft/Silverlight/OutOfBrowser and change permissions from No Access to Read and Write. The application would open fully after that.
Because the behavior was so similar, I checked the same path on my collaborators computer via TeamViewer and found No Access folders but they weren’t the same, that is to say, Silverlight related folders. I didn’t know what they were so I left them alone.