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human
ELI5: How can Robin Williams' will prevents Disney from using his name, taped performances or voice performances or voice recordings for 25 years after his death? Doesn't Disney own the rights to them?

I saw in TIL subreddit today that Robin Williams will prevents Disney for using his name or any of his work for 25 years after his death. But how can he do that when Disney owns the rights ?
gpt
In the contract with Disney for his work on Aladdin, Robin Williams obtained to include a clause giving him power to veto the use of his voice work in other production. It seems his goal then was to avoid being associated with lower quality spin-offs that might have come after the first film.   

In his will, Robin Williams stated that his work shall not be used for 25 years after his death. The purpose of this is to decrease the value of his estate in terms of projected income after his death in order to ease the estate tax burden on his family.   

Disney is still bound by the original Aladdin contract, needing approval from the Williams' estate before using his work. Disney is not directly bound by the will, but Williams' estate is, thus transferring the conditions of the will onto Disney.