Why can't I activate MATLAB or start the license manager properly?

Sometimes, when I start matlab it shows my previous trial licenses instead of my current student licence, and I must to reinitiate it.

How can I to eliminate this error?

Answer 1

[Andreas Goser]

It is not clear to me what "show" means, but there are two aspects: Installation and Licensing. For licensing, there may be license files stored from the trial. You can delete them. You also may have the products you tried - but not purchased - installed. Uninstall them with the Uninstaller