System Message 6908 is received in Dynamics SL when receiving items in for a PO or changing something on any line in a purchase order and saving.
The client has PO Setup configured to automatically insert itemxref records for items. There is one or more items in the PO that have a space in front of the Alternate ID. SL does not recognize spaces, so the program tries to insert a new line, but there is already one in the system (without a space).
To resolve, go through each line of the purchase order and take out the space at the beginning of the Alternate ID’s.