Answer:
Claudius is worried about Hamlet's strange behavior and mental health.
Step-by-step explanation:
Claudius did not want Hamlet to leave back to the university at wittenberg so that they could keep an eye on him.
Hamlet has lost his father the king, and his mother had gone ahead to marry Claudius. Hamlet due to mourning has become a strange and isolated person and no one is sure of his mental state.
Claudius wants him to be close by so that he can monitor/keep an eye on all of Hamlet's moves and ensure he is of no threat