Now the same thing is happening with Photoshop CC.. keeps asking me for serial number, Photoshop CS6 launches normaly with no dialogs, it is only asking for login after I try to start PS CC or Acrobat Pro before him.
Open Illustrator or any other licenced product
Go to Help > Sign Out
Sign in with your adobe id when prompted
Acrobat should work now.
Spent all day figuring this out!