Companies frequently discontinue inventory items. Perhaps an item's sales volume is too low, it has been replaced with a new model, or the item is no longer available from a supplier. By default, in Dynamics GP, discontinued inventory items can still be sold. The reasoning is that companies would still want to sell these items and clear out the inventory if the opportunity arose but they don't want to purchase more of a discontinued item.
The problem comes when companies need to prevent the sale of discontinued items. There could be a safety or health issue contributing to the importance of not selling a particular item. The typical advice in cases like this is to write off the discontinued inventory to prevent the sale. But that removes visibility to inventory that might be returnable for credit in the case of a safety recall. Additionally, in the event of a health issue, the inventory may need to be retained for inspection or proof of proper disposal...