Squealing when Engine starts??

[MarkClaeys]

I changed the sepentine belt and the belt tensioner assembly.
The Alternator spins freely. Ac Compressor doesn't work but the pully spins freely.
When you start the car it squeals, shut it off then start again it doesn't squeal.
Any ideas?

 

[melsg5]

Take a rubber hose hold one end next to your ear and move other end around till you find source of noise.