Prerequisites for activating batch management with inventory already in SAP

hi all,

We have a requirement for a plant to activate batch management where the plant is already running their business in SAP.

Even though we cleared(Movement type 562 ) the stock in the current periods , system still does not allow us to activate batch management in the material master.

Can somebody help us with, What are all the prerequisites to be satisfied before we activate batch management ?

Regards

Gobi