MacBook Pro won't sleep with Thunderbolt display

[Vermillion9494]

I just recently purchased a Thunderbolt Display for my MacBook Pro. I noticed that whenever I put the MBP to sleep that it will go to sleep and then a few seconds later it will wake up. The MBP fans will spin up and the external hard drive that I have connected will spin up too. The display and Thunderbolt display stay dark though until I press a key.

I don't know how to fix this problem and couldn't find any help with a bing/google search.

 

[colshine]

Do you get the same problem with sleeping when the MBP isn't connected to the display?