The system says an item is available, but the person packing the order cannot find it. Another item is on the shelf even though the record says there is none.
A mismatch may come from how stock movements are recorded, rather than a single software fault. Start by following one item through the business.
Look at every movement
List what happens when stock arrives, is put away, reserved for a customer, moved, dispatched or returned. Include damaged items and adjustments after a count.
At each step, ask who records the change and when. If the physical movement happens now but the system is updated later, colleagues may act on information that is already out of date.
Separate available from reserved
An item can be in the building and still be unavailable to another customer because it is committed to an existing order.
Agree what your team means by available, reserved and dispatched. Make sure those definitions are consistent across sales and fulfilment.
In an illustrative example, a cancelled order should release its reservation after the cancellation is confirmed. Otherwise stock can remain tied up even though it is no longer needed for that order.
Investigate differences before correcting them
A count adjustment may make today's number look right without explaining why it was wrong. Keep a record of the reason and look for repeated causes.
Check product codes, units and locations. A box and a single item should not be treated as the same quantity accidentally.
Improve one stock handover
Choose a recurring mismatch and test a focused change. That might be recording receipts at the point of arrival, improving return handling or connecting sales reservations to the stock record.
Automation still needs checks for duplicates, failed updates and unusual returns. Keep an authorised route for investigating and correcting errors.
Measure whether the same difference returns after the change. Reliable stock information comes from agreed working practices and systems that support them, not simply from entering a new opening balance.