Hello @SuzieBarlow
Thanks for posting this in the global Canvas Community!
I am sorry you are having trouble with using the screen capture application. I am assuming you are using the one for Canvas studio?
It sounds like the application either has not downloaded 100% or your computer might be blocking it from launching. After installing it, have you tried to restart your computer? I know this is tedious but in some cases this seems to resolve the issue for some users.
You could also checked to see if something is blocking the application from being launched properly. On Mac that would be in the system preferences under privacy and security. It could also be your browser blocking the application from being launched. In rare cases, I have seen anti virus software block it also. You could check to see if that is the case if you have something like that installed.
Let us know if you find out what is causing this!
-Colton