diff --git a/src/aig/gia/giaAbsGla.c b/src/aig/gia/giaAbsGla.c
index 1732c92e9..56c650118 100644
--- a/src/aig/gia/giaAbsGla.c
+++ b/src/aig/gia/giaAbsGla.c
@@ -854,7 +854,8 @@ int Gia_GlaPerform( Gia_Man_t * pAig, Gia_ParVta_t * pPars )
         pPars->fDumpVabs    = nDumpOld;
         // create gate classes
         Vec_IntFreeP( &pAig->vGateClasses );
-        pAig->vGateClasses = Gia_VtaConvertToGla( pAig, pAig->vObjClasses );
+        if ( pAig->vObjClasses )
+            pAig->vGateClasses = Gia_VtaConvertToGla( pAig, pAig->vObjClasses );
         Vec_IntFreeP( &pAig->vObjClasses );
     }
     if ( RetValue == 0 || pAig->vGateClasses == NULL )
diff --git a/src/aig/gia/giaAbsVta.c b/src/aig/gia/giaAbsVta.c
index 7e4288fce..24856d17c 100644
--- a/src/aig/gia/giaAbsVta.c
+++ b/src/aig/gia/giaAbsVta.c
@@ -1630,24 +1630,29 @@ finish:
     // analize the results
     if ( pCex == NULL )
     {
-        assert( Vec_PtrSize(p->vCores) > 0 );
-        if ( pAig->vObjClasses != NULL )
-            Abc_Print( 1, "Replacing the old abstraction by a new one.\n" );
-        Vec_IntFreeP( &pAig->vObjClasses );
-        pAig->vObjClasses = Gia_VtaFramesToAbs( (Vec_Vec_t *)p->vCores );
-        if ( Status == -1 )
-        {
-            if ( p->pPars->nTimeOut && time(NULL) >= p->pSat->nRuntimeLimit ) 
-                Abc_Print( 1, "SAT solver ran out of time at %d sec in frame %d.  ", p->pPars->nTimeOut, f );
-            else if ( pPars->nConfLimit && sat_solver2_nconflicts(p->pSat) >= pPars->nConfLimit )
-                Abc_Print( 1, "SAT solver ran out of resources at %d conflicts in frame %d.  ", pPars->nConfLimit, f );
-            else if ( p->nSeenGla >= Gia_ManCandNum(pAig) * (100-pPars->nRatioMin) / 100 )
-                Abc_Print( 1, "The ratio of abstracted objects is less than %d %% in frame %d.  ", pPars->nRatioMin, f );
-            else
-                Abc_Print( 1, "Abstraction stopped for unknown reason in frame %d.  ", f );
-        }
+        if ( Vec_PtrSize(p->vCores) == 0 )
+            Abc_Print( 1, "Abstraction is not produced because first frame is not solved.  " );
         else
-            Abc_Print( 1, "SAT solver completed %d frames and produced an abstraction.  ", f );
+        {
+            assert( Vec_PtrSize(p->vCores) > 0 );
+            if ( pAig->vObjClasses != NULL )
+                Abc_Print( 1, "Replacing the old abstraction by a new one.\n" );
+            Vec_IntFreeP( &pAig->vObjClasses );
+            pAig->vObjClasses = Gia_VtaFramesToAbs( (Vec_Vec_t *)p->vCores );
+            if ( Status == -1 )
+            {
+                if ( p->pPars->nTimeOut && time(NULL) >= p->pSat->nRuntimeLimit ) 
+                    Abc_Print( 1, "SAT solver ran out of time at %d sec in frame %d.  ", p->pPars->nTimeOut, f );
+                else if ( pPars->nConfLimit && sat_solver2_nconflicts(p->pSat) >= pPars->nConfLimit )
+                    Abc_Print( 1, "SAT solver ran out of resources at %d conflicts in frame %d.  ", pPars->nConfLimit, f );
+                else if ( p->nSeenGla >= Gia_ManCandNum(pAig) * (100-pPars->nRatioMin) / 100 )
+                    Abc_Print( 1, "The ratio of abstracted objects is less than %d %% in frame %d.  ", pPars->nRatioMin, f );
+                else
+                    Abc_Print( 1, "Abstraction stopped for unknown reason in frame %d.  ", f );
+            }
+            else
+                Abc_Print( 1, "SAT solver completed %d frames and produced an abstraction.  ", f );
+        }
     }
     else
     {