Solution : https://service.sap.com/sap/support/notes/367670 (SAP Service marketplace login required)
Key words :
additional key words xd99, select object kna1, select table massknvk, replace proposed table, select table knvk, maintenance view massknvk, choose 'application tables', table knvk, application table, knvk records
Related Notes :
| 432010 | XD99: Changing mass maintenance from KNVK to MASSKNVK |