diff --git a/src/antares_web_installer/app.py b/src/antares_web_installer/app.py
index cf6cd1e..904a1d0 100644
--- a/src/antares_web_installer/app.py
+++ b/src/antares_web_installer/app.py
@@ -21,7 +21,7 @@
 from antares_web_installer.shortcuts import create_shortcut, get_desktop
 
 # List of files and directories to exclude during installation
-EXCLUDED_FILES = {
+EXCLUDED_ROOT_RESOURCES = {
     Path("config.yaml"),
     Path("archives"),
     Path("internal_studies"),
@@ -188,13 +188,16 @@ def copy_files(self):
         write or if self.target_dir already exists.
         """
         src_dir_content = list(self.source_dir.iterdir())
-        src_dir_content_length = len(src_dir_content)
+        dirs_to_copy = []
+        for root_dir in src_dir_content:
+            if root_dir.relative_to(self.source_dir) not in EXCLUDED_ROOT_RESOURCES:
+                dirs_to_copy.append(root_dir)
+        src_dir_content_length = len(dirs_to_copy)
 
         initial_value = self.progress
 
-        for index, elt_path in enumerate(src_dir_content):
-            relative_elt_path = elt_path.relative_to(self.source_dir)
-            if relative_elt_path not in EXCLUDED_FILES and not elt_path.name.lower().startswith("antareswebinstaller"):
+        for index, elt_path in enumerate(dirs_to_copy):
+            if not elt_path.name.lower().startswith("antareswebinstaller"):
                 logger.info(f"Copying '{elt_path}'")
                 try:
                     if elt_path.is_file():
diff --git a/tests/test_app.py b/tests/test_app.py
index 3017eb3..5645279 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -3,7 +3,7 @@
 
 import pytest
 
-from antares_web_installer.app import App, EXCLUDED_FILES
+from antares_web_installer.app import App, EXCLUDED_ROOT_RESOURCES
 
 
 class TestApp:
@@ -62,8 +62,8 @@ def test_copy_files__nominal_case(self, datadir: Path) -> None:
             content = file.read_bytes()
             old_checksum = old_checksum_by_name[relative_path]
             new_checksum = hashlib.md5(content).hexdigest()
-            root_name = relative_path.parts[0]
-            if root_name in EXCLUDED_FILES:
+            root_name = Path(relative_path.parts[0])
+            if root_name in EXCLUDED_ROOT_RESOURCES:
                 assert old_checksum == new_checksum, f"File {file} must not have been modified"
             else:
                 assert old_checksum != new_checksum, f"File {file} must have been updated"