Diagnosis
You marked the indicator "Mandatory Key Field".

System Response
The meaning of the indicators "Mandatory Key Field" and"Optional Field" is often misunderstood, which is why the systemis sending this warning.

Procedure
Read the documentation for each field: "Mandatory KeyField" and "Optional Field". Then decide if youreally want to create a mandatory key field.
If you want to create a field that will be taken over automatically whenan infostructure is created and which cannot be removed from theinfostructure, you must deactivate the indicator "Optional Field".
If you really want to create a madatory key field, then close thismessage by pressing Enter.