diff --git a/tools/hdltool_readme.txt b/tools/hdltool_readme.txt
index f979f976ec12e4812ca5f7bd089183482515cba3..edeaabcb381db426eeeaedf0d90a902fa087f769 100644
--- a/tools/hdltool_readme.txt
+++ b/tools/hdltool_readme.txt
@@ -532,8 +532,8 @@ c) quartus_* keys and synth_top_level_entity
 d) *_copy_files keys
    . The copy_files() method in hdl_config.py currently uses shutil.rmtree(buildPath), this is probably too risky and
      needs to be made more save to avoid that accidentally some wrong dir tree is removed. Eg. by only accepting
-     shutil.rmtree(buildPath) for subdirectories within $HDL_BUILD_DIR directory and otherwise asking the user to
-     confirm.
+     shutil.rmtree(buildPath) for local subdirectories or subdirectories within the $HDL_BUILD_DIR directory and
+     otherwise exit or ask the user to confirm.
    . The source and destination directory definition needs to be made somewhat more clear. The path can be absolute or
      relative. The relative path can be from hdllib.cfg location in SVN or from the build dir. The direction van be
      from build dir to dir in SVN or vice versa, or to any directory location.
@@ -659,7 +659,7 @@ l) Location of modelsim_project_files.txt
    Default the modelsim_project_files.txt is now created in the SVN directory set by 'toolRootDir'/modelsim. Instead
    the modelsim_project_files.txt should better be created in the build directory 'build_dir_sim'/modelsim/.
    
-m) Issue exit error when a library name occurs double
+m) (FIXED) Issue exit error when a library name occurs double
    When a HDL library directory is copied and the hdllib.cfg is not updated then the library name will be double
    and cause misalignenment errors in the libraries lists which are difficult for a user to diagnose. The
    _init__ in hdl_config.py could check this.
diff --git a/tools/oneclick/base/hdl_config.py b/tools/oneclick/base/hdl_config.py
index fd062351adfbedd5766945c9c1a66a4194538f3d..55b90fba05ec6d5cce5d253debaedae892fcf4dc 100644
--- a/tools/oneclick/base/hdl_config.py
+++ b/tools/oneclick/base/hdl_config.py
@@ -79,6 +79,13 @@ class HdlConfig:
         self.libs = common_dict_file.CommonDictFile(libRootDir, libFileName)        # library dict files
         if self.libs.nof_dicts==0: sys.exit('Error : No HDL library config file found')
         
+        # Keep list of HDL library names
+        self.lib_names = self.libs.get_key_values('hdl_lib_name')
+        
+        # Check that there are no duplicate library names (eg. due to copying a hdlib.cfg without modifying the hdl_lib_name value)
+        duplicate_lib_names = cm.list_duplicates(self.lib_names)
+        if len(duplicate_lib_names)>0: sys.exit('Error : Duplicate HDL library config file found %s' % duplicate_lib_names)
+
         # Keep the generic HDL libraries and remove those that do not match the specified IP technologies
         self.technologyNames = cm.listify(technologyNames)
         self.removed_dicts = []
@@ -88,9 +95,7 @@ class HdlConfig:
                     self.removed_dicts.append(d)
             for d in self.removed_dicts:
                 self.libs.remove_dict_from_list(d)
-            
-        self.lib_names = self.libs.get_key_values('hdl_lib_name')
-        
+                
     def derive_all_use_libs(self, lib_name):
         """Derive a list of all HDL libraries that the specified HDL lib_name library depends on.