Here is one I have not encountered before. (Inventory 9.2A)

I have a stocking item that had quantities that I needed to change to non-stock. The quantities and costs were reduced to zero and show zero on item inquiries and the Stock Card report.

When I try to change it to stocking FALSE IC reports that it can't because the item has quantities. Integrity checks fine.

Any suggestions?

Is the item using FIFO or LIFO costing? It's possible that you have positive and negative quantities in separate buckets. An adjustment, changing the costing to average costing or GV-RW can fix it.

The item is set for user defined costing so no buckets involved.

ICILOC had a Qty of -0.25 which was why we could not change the item to an item that was not stocked.
Inventory integrity check as far as I know did not report this as an error and as a result did not fix it.
We used one of our internal utilities to zero the quantity and we are good to go.