Import job to bring vendor invoices into Pending AP Vouchers had been running successfully for 10 months.  The source file is Excel, and new rows (records) have been added from a different system that hadn't provided anything to import previously.  Upon completion, the summary window showed 100% complete but 0 records read.  SQL Agent Log had many warnings similar to the following:

Code: 0x800470C8     Source: Import DataFlow Lines$_StgVoucherDetl [35]     Description: The external columns for component "Lines$_StgVoucherDetl" (35) are out of synchronization with the data source columns. The external column "Invoice No" needs to be updated.  The external column "Unit Cost" needs to be updated.  The external column "Extended Cost" needs to be updated.  The external column "F15" (90) needs to be removed from the external columns.  End Warning

Does anyone know what needs to be done?  Not sure what the "external columns" are referencing, or what it means by needing to update or remove columns from them.

Would greatly appreciate help on this!  Thank you!