Where you downloaded the Yosemite, I would like to download to test ?
you need to be registered as Mac developer currently to login on Apple’s website and get a code to redeem it from the Mac App Store.
You don’t need to this year. There’s a free public beta at
Welcome to the new Apple.
I don’t know if it gives you instant access, as I’ve a developer account.
Thanks, Gavin 
(I’m holding off on a paid membership until I’m ready to release my in-the-works app)
Tanks People !