Error "License Key Already in Use"

When I try to start a show I receive the above error message?

As the error message implies, it looks like the license key is already in use. Make sure you do not have a second show online on you computer. Or, that you are using the Dynamic Image Server (which requires a license of its own).

This error message typically occurs when the user has inadvertently started more than one copy of WATCHOUT Production. It will also occur if WATCHNET is open in the background. Quit all copies of WATCHOUT Production and confirm WATCHNET is not started, try again.