I downloaded the Storm Island DLC and paid for it obviously and it isn’t there. It is still greyed out. I rebooted the console, cleared the cache, I uninstalled and installed it again, I tweeted to Turn 10 Studios 2 times with no answer, I looked on Google and many have the same problem. I also notice that every answer is different from one person to the next and nobody seems to know what the hell is going on. This is poor customer service on the part of Turn 10 to be honest because I have tried to contact them with no luck. Apparently, others have done the same thing with no luck either. It would be nice if someone had an answer for me. All I can do is try.
How did u install it , once bought
Ive got the same problem but as a complete newby gamer dad of an 8 year old who is very frustrated I dont know where to start. Any help anyone?
I had the same problem when i purchased and installed it on my console what i ended up having to do was finish the current championship i was in then i was prompted with the introduction n stuff n told to head to the docks to travel to storm island i hope this helps. 
Hello all,
Might be old news, but I was among the ones who had trouble unlocking the storm island DLC, but all I had to do was complete a championship and it unlocked.
Yeah, it’s pretty early on in the game. I think it’s right after the showcase where you race Fat Albert in the Jaguar.