SAP Message R7546 - Char. &1 is a navigation attr. of &2: Exclusively attribute not possible

Diagnosis
Characteristic &V1& is still being used a navigation attribute ofInfoObject &V2&. InfoObjects, that are exclusively attributes, cannotbe used as a navigation attribute. Therefore, you are not allowed toswitch on the property 'Exclusively attribute' for characteristic &V1&.

System Response
Characteristic &V1& cannot be activated.

Procedure
Before you can make characteristic &V1& an exclusively attribute itmust cease to be used as a navigation attribute. &SYS_ADMIN&