File - Run - *UTL

Try the inventory rebalancing utility (in a test company first... pay attention to the utility pop-ups as they are critical).  There may be data inconsistencies in the different inventory tables.

Thank you Kevin,  I will try

If it shows zero (0) quantity on hand in the display panels you should rebuild the sort files first. 

If the bad value was "Available" (vs On Hand), Rebuild Sort Files would certainly be worth trying first (since that is a much less involved utility).