How come when I download a sim from the sims 3 exchange it says failed?

Now the sims I'm trying to download have custom made clothes and hair. Could that be the reason? I also have a mac. But if I download sim clothes from the exchange it works fine.How come when I download a sim from the sims 3 exchange it says failed?It could, indeed be, that the Sim you are trying to download does require custom content either clothes, hair, or whatever. Also, it might be a Sim using World Adventures. Unless, of course you have World Adventures then it would be no problem.

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