diff --git a/MMVII/src/Utils/uti_string.cpp b/MMVII/src/Utils/uti_string.cpp
index cf57bdc0f8..da9cc0bd2f 100755
--- a/MMVII/src/Utils/uti_string.cpp
+++ b/MMVII/src/Utils/uti_string.cpp
@@ -584,6 +584,7 @@ void  MakeBckUp(const std::string & aDir,const std::string & aNameFile,int aNbDi
 
 void GetFilesFromDir(std::vector<std::string> & aRes,const std::string & aDir,const tNameSelector &  aNS,bool OnlyRegular)
 {
+    MMVII_INTERNAL_ASSERT_User(IsDirectory(aDir), eTyUEr::eOpenFile, aDir+" is not a directory!");
     for (fs::directory_iterator itr(aDir); itr!=fs::directory_iterator(); ++itr)
    {
       std::string aName ( itr->path().filename().generic_string().c_str());
@@ -618,6 +619,7 @@ std::vector<std::string> GetSubDirFromDir(const std::string & aDir,const tNameSe
 */
 void RecGetFilesFromDir( std::vector<std::string> & aRes, const std::string & aDir,tNameSelector  aNS,int aLevMin, int aLevMax)
 {
+    MMVII_INTERNAL_ASSERT_User(IsDirectory(aDir), eTyUEr::eOpenFile, aDir+" is not a directory!");
     for (fs::recursive_directory_iterator itr(aDir); itr!=fs::recursive_directory_iterator(); ++itr)
     {
         int aLev = itr.depth();