You have already maintained a BOM in this transaction

What causes this issue?

You want to create or change a bill of material (BOM) for the material
&V2&. However, you have already created or changed a BOM for the
material &V1& in this transaction. Only one BOM can be processed in a
transaction.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Save your data. Call up the transaction again and then process the BOM
for the material &V2&.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.