Diagnosis
You want to set the "Entry required" indicator, so that a value has tobe assigned to this characteristic.
Objects have already been classified using this class. An analysis ofvalues already assigned has shown that, in one or more cases, no valuehas been assigned to the characteristic. This contradicts the aboveindicator.

Procedure
Deselect the field.
If you really want to enter this indicator, first check all valuesassigned to this characteristic and assign values wherever no value hasbeen assigned.
If you choose Environment -> Where-used list from thecharacteristics maintenance menu, you can find out where thecharacteristic has been used.