Sage 100 Error: "The lot serial number is invalid"


“The lot serial number is invalid” when selecting a serial item in Sales Order Shipping Data Entry.


Invalid GroupSort field value in the IM_ItemCost field


  1. Open Library Master, Utilities, Data File Display, and Maintenance
  2. Browse to MAS_xxx and look in the file IM_ItemCost.m4t file (where xxx is the Company).
  3. In the Key field enter the part number in question.
  4. Click the lookup button and select the item with the correct serial number and warehouse.
  5. Look at field 04 GroupSort$
  6. Compare to field 07 LotSerialNo$
  7. Click Edit.
  8. Edit field 04 GroupSort$ to match field 07 LotSerialNo$
  9. Click Yes to “Remove Old Key”