SAP Message WSTI_MM07I001 - The difference cannot be posted (calculate book inventory first)

Diagnosis
The procedure for supporting physical inventory during opening times inplant &V1& and storage location &V2& is activated. Therefore, the bookinventories for the counted items in a physical inventory document mustbe calculated at count time before the physical inventory differencesfor these items can be posted. However, no book inventories at counttime have been calculated for any of the items counted in physicalinventory document &V3&.

System Response
The system will not allow you to post the differences for document &V3&.

Procedure
Execute the calculation of book inventories at count time. Then you canpost the physical inventory differences.