Hello, I am having the same problem. We are trying to enter a bill, which should increase our on hand quantity so it should not need changing? The last purchase price was entered incorrectly at 4800, instead of 48, I suspect this is the problem but we cannot edit the last purchase price and it will not let me enter the new one. Very frustrating. If we are adding inventory surely it should let us enter at the current price and update the on hand quantity and inventory accordingly? Why would entering new stock create a negative value in inventory?