diff --git a/GeomDB.cpp b/GeomDB.cpp
index 920f964..b1dd084 100644
--- a/GeomDB.cpp
+++ b/GeomDB.cpp
@@ -45,12 +45,12 @@ CreateGeomDB( void)
       if ( nRet != KEY_OK) {
          string sErr = "Error on Key (GKC/" + ToString( nRet) + ")" ;
          LOG_ERROR( GetEGkLogger(), sErr.c_str()) ;
-         return false ;
+         return nullptr ;
       }
       if ( (nOpt1 & KEYOPT_EGK_BASE) == 0  ||  nOptExpDays < GetCurrDay()) {
          string sErr = "Error on Key (GKC/OPT)" ;
          LOG_ERROR( GetEGkLogger(), sErr.c_str()) ;
-         return false ;
+         return nullptr ;
       }
    }
   // creo il GeomDB