diff --git a/Post/PViewDataGModelIO.cpp b/Post/PViewDataGModelIO.cpp
index 9e8526776e97df28f140b31b99121332d0d4e719..f810594f900cb4c760ecaf92131fcc3ee96d7d9d 100644
--- a/Post/PViewDataGModelIO.cpp
+++ b/Post/PViewDataGModelIO.cpp
@@ -174,6 +174,7 @@ bool PViewDataGModel::writeMSH(std::string fileName, bool binary)
               return false;
             }
             int num = v->getIndex();
+            if(num < 0) num = 0;
             if(binary){
               fwrite(&num, sizeof(int), 1, fp);
               fwrite(_steps[step]->getData(i), sizeof(double), numComp, fp);