Note if you are running Media Composer First and want to use Media Composer Ultimate trial license you will have the option if you sign up for the Media composer Ultimate Trial

See Link to the left

I'm running Media Composer | First: I want to try the Media Composer Ultimate trial what should I do? (force.com)
Once you sign up for the trial you will get the option to Run the Trial seen here

Yes here is how to fix the issue.  You will need to deactivate your Ultimate version then you will see only MC first
Open AVID Link and go to License

Then Deactivate your Ultimate license so you only see Media composer first and OPEN it

Then choose to open MC First here


Then when you are ready to use Ultimate you need to activate it again and that should be easy to do when you click AVID Link>Media Composer>License