What should you do if you have negative inventory reflected in your system?
You should do a cycle count or inventory adjustment, but first, do a review of the inventory or location history to determine when this happened.
If a negative inventory is allowed, it most likely will be corrected upon receipt of the item. For example, assume that there is a PO that has not been received in Baan/LN, but the goods came in and got shipped out on a sales order. The inventory goes negative, but when the PO receipt is entered, the inventory would be corrected. In this case, no adjustment should be made.
A little due diligence will go a long way to ensure that you are only making an adjustment to your system when warranted.