New and tight alternator belt squeels

[rcx106]

As the title says the belt is brand new and tight but still squeels sometimes for a few seconds when I first start the car. Could I have damaged the pulleys by running a slipping belt before for too long? The alternator belt pulley looks discoloured from overheating :/

Maybe the pulley contact faces need roughing up somehow?

[rcx106]

Hi. It's a Vitara. No clutch on the alternator pulley. The alternator belt is driven by the crankshaft pulley (very large) and also drives the water pump. It's a four groove belt.