You will get this message when you try to edit or delete a sale that caused inventory to go negative and the negative quantities have been satisfied by a purchase or receive items transaction. The sequence goes like this:

Create a sale for items for which you have no inventory on hand - creating negative quantity and value on the items list. Record a purchase order on which you receive these same items - or create a bill on which you purchase these same items.

When you do this, AccountEdge creates adjustment entries for the Cost of Goods account, for any sales that contained these items - to ensure that the average cost is maintained on negative sales.

You can see these adjustment entries in the Inventory Journal.

Click on the adjustment entry to view it. The Sale for which the Cost of Goods is being adjusted is noted in the memo field.