Invalid BC Set activation component assignments

What causes this issue?

You want to activate one or more BC Sets, but one or more of the
specified BC Sets are assigned to software components which are not in
the activation system.

System Response

The activation is cancelled, without writing data in the system. If you
are activating several BC at the same time, those with valid software
components are not activated either.

How to fix this error?

Check which software components are in your system or system landscape,
and which components are assigned to the affected BC Set(s). Only
activate valid BC Sets.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.