If you come across a missing or illegible barcode while checking an item in or out, you will have to manually look up the item. The procedure for this is the same in both cases, though the overall screens will look slightly different.
If the item's barcode is missing or not working, you can manually look up the item with the "Select from a list" button next to the "Scan item barcode" field.
The checking in screen:
The checking out screen:
An additional Physical Items screen will open, allowing you to select from the "Choose search index", "Choose search scope", and "Advanced" menus.
Locate your correct item record and click on the Title/Author to populate the "Scan item barcode" field.
Click on the "OK" button to check the item in/out.
If the item is being returned, send it to Technical Services for a new barcode.