Hi Henry

I'm not sure what modules you are using, but assuming it's OrderEntry and Inventory....

1) Make a backup of your data
2) Perform dayend processing in OE
3) Run Data Integrity Check in OE - when it reports errors, click on Rebuild to fix them, then repeat this step until there are no errors
4) Run Data Integrity Check in IC - same situation as OE

If this doesn't work, let us know.

Steve