
'%s' for item '%s' in line %s already exists (in unique field)
In the Serial Numbers - Setup window, you have tried to manually assign the same serial number to more than one unit of a specific item, and have chosen Update. According to your company configuration, you are required to assign a unique serial number to each unit of an item for which serial numbers are managed (from , choose the Inventory tab and the Items subtab, in the Unique Serial Numbers by field, select Serial Number).
In the Serial Numbers - Setup window, in the Created Serial Numbers section, select the row that shares multiple-used serial numbers and from the context menu, choose Delete. If you have assigned the same serial number to more than two units of the same item, repeat this step as many times as required, until only one instance of a specific serial number is left.
Assign a unique serial number to each unit of the specific item and choose Update.
Note
To assign a large quantity of serial numbers, use the Automatic Creation option.