Movies and tv programmes won't start in a completely properly set up all apple environment

Hello and welcome to Apple Support Communities, DazeRof.

If I understand your post correctly, a movie that you purchased from iTunes will not play on your updated MacBook Pro but plays on another computer. I'd like to help.

First, try this reset:

Reset NVRAM or PRAM on your Mac

If this issue continues after that reset, let's do some testing to narrow down the issue.

Safe mode will tell us if the issue is related to a startup item or plugins, and sometimes corrects the issue. This article will tell you how: Use safe mode to isolate issues with your Mac

If everything is working correctly in safe mode, but is not working when you get back to your user account, please check the section titled "If an issue doesn't happen in safe mode" for the next troubleshooting steps.

If the issue continues while in safe mode, a test user will let us know if the issue is isolated to your account, or system wide: How to test an issue in another user account on your Mac. If the issue happens in the test user also, then please check the section titled "If an issue happens in more than one user account."

Let us know if that resolves this issue for you. 

Thanks for using the Apple Support Communities. Take care.