Selection list box number &1 already has a standard value

What causes this issue?

You want to maintain a selection criteria as a standard value (default)
for selection list box number &v1& of the selection criteria.
However, you already selected a criterion as a standard value for this
list box.

System Response

Maintaining the standard value is not possible.

How to fix this error?

If you want to maintain a new standard value, first delete the old
standard value.

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.