diff --git a/src/base/abci/abcSymm.c b/src/base/abci/abcSymm.c
index 8f6bc9699..d5cf7a44e 100644
--- a/src/base/abci/abcSymm.c
+++ b/src/base/abci/abcSymm.c
@@ -327,7 +327,10 @@ void Ntk_SymFunGenerate( int nVars, int fVerbose )
         if ( fVerbose )
             Extra_PrintHex( stdout, (unsigned *)pFun, nVars );
         Ntk_SymFunDeriveNpn( pFun, nVars, pComp );
+        //int nClasses = Vec_MemEntryNum( vTtMem );
         Class = Vec_MemHashInsert( vTtMem, pFun );
+        //if ( Class == nClasses )
+        //printf( "Class %3d : %s\n", nClasses, Ones );
         if ( fVerbose )
         {
             printf( " : NPN " );
diff --git a/src/base/cmd/cmdHist.c b/src/base/cmd/cmdHist.c
index b66f48c88..0edd8a686 100644
--- a/src/base/cmd/cmdHist.c
+++ b/src/base/cmd/cmdHist.c
@@ -160,9 +160,15 @@ void Cmd_HistoryWrite( Abc_Frame_t * p, int Limit )
             return;
         }
         Limit = Abc_MaxInt( 0, Vec_PtrSize(p->aHistory)-Limit );
-        Vec_PtrForEachEntryStart( char *, p->aHistory, pStr, i, Limit )
+        Vec_Ptr_t * aHistory= Vec_PtrAlloc(Vec_PtrSize(p->aHistory));
+        Vec_PtrForEachEntryStart( char *, p->aHistory, pStr, i, Limit ) {
             fprintf( pFile, "%s\n", pStr );
+            Vec_PtrPush( aHistory, Abc_UtilStrsav(pStr) );
+        }
         fclose( pFile );
+        Vec_PtrFreeFree( p->aHistory );
+        p->aHistory = aHistory;
+        p->iStartHistory = Vec_PtrSize(p->aHistory);
     }
 #endif
 }