diff --git a/tugui/gui_widgets.py b/tugui/gui_widgets.py
index 889527e..59d9584 100644
--- a/tugui/gui_widgets.py
+++ b/tugui/gui_widgets.py
@@ -38,45 +38,30 @@ def __init__(self, frame: tk.Frame, width: int, col: int, row: int,
 
   def validate(self, entry_txt: str = "") -> bool:
     """
-    Method that checks if the entry is valid. The "end" parameter indicates the
-    extension to check against.
+    Method that checks if the entry is valid.
     """
-    # Do not check anything if the entry is empty; return immediately
+    # Return if the entry is empty
     if not entry_txt:
       return True
     # Check the entry value according to the validation function
     try:
       self.validation_func(entry_txt, self.entry_extension)
+      # FIXME: to add the following message into the log file
       print("The entry is valid!")
       self.entry.configure(foreground="#343638")
       # Generate a virtual event stating that the entry is valid
       self.entry.event_generate("<<Valid-Entry>>")
       return True
     except Exception as e:
-      # Get the exception error message
-      error_message = str(e)
       # Handle the invalid case
-      self.on_invalid(error_message)
+      self.on_invalid(str(e))
       return False
 
-    # if re.match(r"^.*\." + self.entry_extension + "$", entry_txt) is not None:
-    #   # The entry is valid if a match is found
-    #   print("The entry is valid!")
-    #   self.entry.configure(foreground="#343638")
-    #   # Generate a virtual event stating that the entry is valid
-    #   self.entry.event_generate("<<Valid-Entry>>")
-    #   return True
-    # else:
-    #   # If no match is found, handle the invalid case only if the entry value is not empty
-    #   if entry_txt != "":
-    #     self.on_invalid()
-    #     return False
-
   def on_invalid(self, error_message: str) -> None:
     """
     Show the error message if the data is not valid.
     """
-    # error_message = "The entry is not valid: please provide a path to a file with the valid \"" + self.entry_extension + "\" extension!"
+    # FIXME: to add the following message to the log file
     print(error_message)
     # Highlight the entry color in red
     self.entry.configure(foreground="red")
diff --git a/tugui/main.py b/tugui/main.py
index 902ad97..a2e9cb8 100644
--- a/tugui/main.py
+++ b/tugui/main.py
@@ -788,7 +788,7 @@ def __select_file_and_fill_entry(self, entry: ttk.Entry, fileToSearch: str, form
     # and retrieve the path of the selected file.
     filename = self.__select_file(fileToSearch, format)
 
-    # Delete any already present path in the given entry
+    # Delete the content of the entry, if any
     entry.delete(0, tk.END)
     # Insert the selected file path in the given entry
     entry.insert(0, filename)
diff --git a/tugui/support.py b/tugui/support.py
index 2b60114..2edc0d6 100644
--- a/tugui/support.py
+++ b/tugui/support.py
@@ -77,43 +77,39 @@ def description(self) -> str:
     return self.value[1]
 
 
-def check_file_existence(file_path: str, file_extension: str) -> None:
+def check_file_existence(file_path: str) -> None:
   """
-  Function that can be accessed globally for checking if the given
-  file path exists and is a file. If not, the function raises an
-  exception.
+  Function for checking if the given file path exists and is a file.
+  If not, the function raises an exception.
   """
   if not os.path.isfile(file_path):
     # If the file does not exists, throw an exception
-    raise Exception(f"Error: the .{file_extension} file does not exist at the specified path.")
+    raise Exception(f"Error: file {file_path} does not exist!")
 
 def check_file_extension_and_existence(file_path: str,
                                        file_extension: str) -> None:
   """
-  Function that can be accessed globally for checking if the given
-  file has the correct instance, its path exists and corresponds to
-  a file. If so, True is returned; False otherwise.
+  Function for checking if the given file has the correct extension and
+  exists. If so, True is returned; False otherwise.
 
   Parameters
   ----------
-  file_path       : str
-      The path to the file to check
+  file_path : str
+      The path to the file to check.
   file_extension  : str
-      The extension the file must have and is checked for
+      The extension the file must have and is checked for.
 
   Raises
   ------
   An Exception if the file extension does not match with the required
-  one or the file does not exists at the specified path
+  one or the file does not exist.
   """
+  # Check the extension
   extension = os.path.splitext(file_path)
-  print("Extension", extension)
   if not (extension[1] == '.' + file_extension):
       # The file specified by the given path has not the correct extension
       raise Exception(f"The indicated file with extension '{extension[1]}' is "
                       "not valid. Please provide one with the "
                       f"'{file_extension}' extension.")
-  if not os.path.isfile(file_path):
-      # The file does not exists
-      raise Exception(f"Error: the file specified by the '{file_path}' path "
-                      "does not exist.")
+  # Check the existence
+  check_file_existence(file_path)
diff --git a/tugui/tu_interface.py b/tugui/tu_interface.py
index 0db099e..4553ff3 100644
--- a/tugui/tu_interface.py
+++ b/tugui/tu_interface.py
@@ -199,11 +199,11 @@ def save_loaded_inp(self) -> str:
       else:
         plireader = PliReader.init_PliReader(os.path.join(self.inp_dir, diagr.pli_name))
       # Check if any of the DAT files is missing
-      check_file_existence(os.path.join(self.inp_dir, plireader.mac_path), 'mac')
-      check_file_existence(os.path.join(self.inp_dir, plireader.mic_path), 'mic')
+      check_file_existence(os.path.join(self.inp_dir, plireader.mac_path))
+      check_file_existence(os.path.join(self.inp_dir, plireader.mic_path))
       # Check the .sta file existence only if required, i.e if the 'ISTATI' field is '1'
       if plireader.opt_dict['ISTATI'] == 1:
-        check_file_existence(os.path.join(self.inp_dir, plireader.sta_path), 'sta')
+        check_file_existence(os.path.join(self.inp_dir, plireader.sta_path))
 
     # Declare a string holding the .inp filename (with default to 'TuPlot')
     filename = "TuPlot.inp"
@@ -451,8 +451,6 @@ def init_PliReader(pli_path: str) -> Self:
     This method returns the built instance of the 'PliReader' class.
     """
     # Check the .pli file existence
-    # FIXME to delete as already performed by the entry widget
-    # check_file_existence(pli_path, 'pli')
     # Get the path to the .pli file directory
     pli_dir = os.path.dirname(pli_path)
     # Instantiate the 'PliReader' class
@@ -521,7 +519,7 @@ def __init__(self, da_path: str, extension: str) -> None:
     direct-access file to read and checks its actual existence.
     """
     # Check the direct-access file existence
-    check_file_existence(da_path, extension)
+    check_file_existence(da_path)
     # Store the direct-access file path
     self.da_path: str = da_path
     # Initialize the time values read from the direct-access file