If you lose your physical packaging and cannot access the software interface, check your company's original procurement records or IT asset management logs. FANUC distributors can sometimes recover license details if you can provide the original purchase order number or invoice. "Invalid Serial Number" Errors If the installer rejects your input, verify the following:
A common frustration among new users is the sudden expiration of the software. Some LADDER-III serial numbers are (evaluation keys) and will expire after a certain period. When this happens, a warning popup will appear indicating the license has expired. The solution is to uninstall the existing LADDER-III instance and re-install using a permanent serial number, rather than the temporary trial key. fanuc ladder iii serial number