diff --git a/muk_utils/__manifest__.py b/muk_utils/__manifest__.py
index 29e154b..3ff7757 100644
--- a/muk_utils/__manifest__.py
+++ b/muk_utils/__manifest__.py
@@ -20,7 +20,7 @@
 {
     "name": "MuK Utils",
     "summary": """Utility Features""",
-    "version": '11.0.1.0.10',   
+    "version": '11.0.1.0.11',   
     "category": 'Extra Tools',   
     "license": "AGPL-3",
     "website": "https://www.mukit.at",
diff --git a/muk_utils/tools/utils_os.py b/muk_utils/tools/utils_os.py
index 713ab6e..2fcafac 100644
--- a/muk_utils/tools/utils_os.py
+++ b/muk_utils/tools/utils_os.py
@@ -50,7 +50,7 @@ def get_extension(filename, mimetype):
         mimetype = guess_mimetype(binary, default=False)
     if not mimetype and filename:
         mimetype = mimetypes.guess_type(urllib.request.pathname2url(filename))[0]
-    if not filename and mimetype:
+    if mimetype and mimetype != 'application/octet-stream':
         return mimetypes.guess_extension(mimetype)[1:].strip().lower()
     elif filename:
         return os.path.splitext(filename)[1][1:].strip().lower()