If you enter a quantity in the Quantity field on an order line that is greater than the inventory, or if you convert a quote in which the quantity is greater than the inventory, a message will appear. This message tells you that there is not enough in inventory to cover the net change in inventory.
You can choose not to have this kind of stockout warnings.
Open the Sales & Receivables Setup window.
On the General tab, click the Stockout Warning field to remove the check mark.
Eliminating Credit Limit Warnings
Eliminating Overdue Balance Warnings