diff --git a/nxscript.c b/nxscript.c
index 1d7375d1..f04b73df 100644
--- a/nxscript.c
+++ b/nxscript.c
@@ -732,12 +732,14 @@ static void putSlab(SConnection *pCon, SicsInterp *pSics, pNXScript self,
             hpars[haStart],hpars[haStart]+hpars[haLength],histData,
             hpars[haLength]*sizeof(HistInt));
       }
-        if(histData){
-            status = NXputslab(self->fileHandle, histData, start, size);
-            if(status == NX_OK){
-                written = 1;
-            }
+      if(histData){
+        status = NXputslab(self->fileHandle, histData, start, size);
+        if(status == NX_OK){
+          written = 1;
         }
+        if (argc > 6)
+          free(histData);
+      }
     }
     
     /*