Diagnosis
Apportionment units and area types from Classic RE are automaticallyconverted to measurements in RE-FX. However, if you have apportionmentunits that have the same keys as area types, this automatic conversionis not possible. You need to assign new keys for these apportionmentunits in Customizing for the conversion.

Procedure
Before you can execute the Convert Customizing step, you have toenter a measurement type for the apportionment unit in conversionCustomizing.
Master Data: Define Measurement Types forArea Type and Apportionment Unit