Diagnosis
The benchmark is used in a version of a composite benchmark orassignment variant that is no longer active.

Procedure
Delete the version of the benchmark.
The system deletes straight away any versions that have no reference tothe history of a composite benchmark or an assignment variant.
It deletes versions that do have a reference only once you have entereda reason. These versions are then flagged as invalid. You can stilldisplay them in the change history of the higher-level compositebenchmark or assignment variant.