Diagnosis
You want to create a variant for the BOM for material &V1&.
A multiple BOM already exists for the material/plant/usage.
A variant can only be created for a material if its BOM only containsone alternative or if the BOM is already a variant BOM.

Procedure
You have two options:
Enter another material and press ENTER.
Check your entries on the initial screen for the plant and usage.
Cancel the transaction Create variant for... using function keyF12, so you can correct your entries on the intitial screen. Thenchoose the function Create variant for... again.