Is it permissible to use the "macOS" operating system on a computer not manufactured by Apple, for the purpose of learning, or on the pretext that the disc is the property of the buyer?

It is permissible for the owner of the operating system to install it on any device he wishes, and he is not obliged to fulfill a condition if it contradicts the essence of the contract. The essence of a valid sale is the transfer of ownership of the sold item to the buyer, and in such a case, he is permitted to dispose of it by placing it wherever he desires.