2760451 - Got error "Problem saving the connection" when saving business layer after deleted primary key

• Unable to save specific universe after deleted primary key from Business Layer
• Error message:
  

  Problem saving the connection.

  Failed to execute runnable (com.sap.tools.commons.exception.NestedException: The object 'com.businessobjects.mds.universe.business.impl.AttributeImpl@xxxxx(identifier: _xxxxx) (coreItemIdentifier: , overridableProperties: -1) (businessName: Primary Key, description: null, state: Active, position: 0.0) (dataType: String, access: Public, forResult: true, forFilter: true, forSort: true, displayHint: NONE, databaseFormat: null, lineage: null, mapping: null, technicalInformation: null, withListOfValues: true, lovMappingIndex: 0, lovEditable: false, lovRefreshable: false, lovSearchable: false, lovFilterBeforeUse: false) (type: PrimaryKey, aggregatable: true)' is not contained in a resource.)

• SAP BusinessObjects BI Platform 4.1 / 4.2 
• Information Design Tool

primary key, delete key, save unx, bl, bi 4.2, 4.1, idt, PrimaryKey , KBA , BI-RA-WBI , Web Intelligence , Problem