diff --git a/antarest/launcher/service.py b/antarest/launcher/service.py
index 3a50cf91cb..a8e12e4da7 100644
--- a/antarest/launcher/service.py
+++ b/antarest/launcher/service.py
@@ -474,9 +474,9 @@ def _import_output(
             study_id = job_result.study_id
             job_launch_params = LauncherParametersDTO.parse_raw(job_result.launcher_params or "{}")
 
-            # this now can be a zip file instead of a directory !
+            # this now can be a zip file instead of a directory!
             output_true_path = retrieve_output_path(output_path)
-            output_is_zipped = is_zip(output_true_path)
+            output_is_zipped = output_true_path.suffix.lower() == ".zip"
             output_suffix = cast(
                 Optional[str],
                 getattr(
diff --git a/antarest/study/storage/utils.py b/antarest/study/storage/utils.py
index f429fc5e55..50f12e996c 100644
--- a/antarest/study/storage/utils.py
+++ b/antarest/study/storage/utils.py
@@ -115,14 +115,17 @@ def fix_study_root(study_path: Path) -> None:
 
 
 def retrieve_output_path(job_path: Path) -> Path:
-    inside_study_output_path = job_path / "output"
     output_already_zipped_path = job_path.with_suffix(".zip")
     if output_already_zipped_path.exists():
         return output_already_zipped_path
-    elif inside_study_output_path.exists() and len(os.listdir(inside_study_output_path)) == 1:
-        return inside_study_output_path / os.listdir(str(inside_study_output_path))[0]
-    else:
-        return Path()
+
+    output_inside_study = job_path / "output"
+    if output_inside_study.is_dir():
+        output_folders = os.listdir(output_inside_study)
+        if len(output_folders) == 1:
+            return output_inside_study / output_folders[0]
+
+    return Path()
 
 
 def extract_output_name(path_output: Path, new_suffix_name: Optional[str] = None) -> str: