Restriction of client packages activated, but no package entered

What causes this issue?

The option "Activate Restriction of Client Packages" is activated for
package interface &V1&; however, the list of client packages does not
contain any entries.
As a result, no package can access this package interface.

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?

Deactivate this option or enter client packages in the list.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.