diff --git a/gns3server/modules/base_manager.py b/gns3server/modules/base_manager.py
index b8e2512a..110f2c12 100644
--- a/gns3server/modules/base_manager.py
+++ b/gns3server/modules/base_manager.py
@@ -486,14 +486,17 @@ class BaseManager:
         log.info("Writting image file %s", path)
         try:
             remove_checksum(path)
+            # We store the file under his final name only when the upload is finished
+            tmp_path = path + ".tmp"
             os.makedirs(os.path.dirname(path), exist_ok=True)
-            with open(path, 'wb+') as f:
+            with open(tmp_path, 'wb+') as f:
                 while True:
                     packet = yield from stream.read(512)
                     if not packet:
                         break
                     f.write(packet)
-            os.chmod(path, stat.S_IWRITE | stat.S_IREAD | stat.S_IEXEC)
+            os.chmod(tmp_path, stat.S_IWRITE | stat.S_IREAD | stat.S_IEXEC)
+            shutil.move(tmp_path, path)
             md5sum(path)
         except OSError as e:
             raise aiohttp.web.HTTPConflict(text="Could not write image: {} because {}".format(filename, e))
diff --git a/tests/handlers/api/test_dynamips.py b/tests/handlers/api/test_dynamips.py
index ba652b5f..fa201970 100644
--- a/tests/handlers/api/test_dynamips.py
+++ b/tests/handlers/api/test_dynamips.py
@@ -173,9 +173,9 @@ def test_upload_vm(server, tmpdir):
 
 
 def test_upload_vm_permission_denied(server, tmpdir):
-    with open(str(tmpdir / "test2"), "w+") as f:
+    with open(str(tmpdir / "test2.tmp"), "w+") as f:
         f.write("")
-    os.chmod(str(tmpdir / "test2"), 0)
+    os.chmod(str(tmpdir / "test2.tmp"), 0)
 
     with patch("gns3server.modules.Dynamips.get_images_directory", return_value=str(tmpdir),):
         response = server.post("/dynamips/vms/test2", body="TEST", raw=True)
diff --git a/tests/handlers/api/test_iou.py b/tests/handlers/api/test_iou.py
index 60c39d88..2dbb4011 100644
--- a/tests/handlers/api/test_iou.py
+++ b/tests/handlers/api/test_iou.py
@@ -349,11 +349,3 @@ def test_upload_vm(server, tmpdir):
         assert checksum == "033bd94b1168d7e4f0d644c3c95e35bf"
 
 
-def test_upload_vm_permission_denied(server, tmpdir):
-    with open(str(tmpdir / "test2"), "w+") as f:
-        f.write("")
-    os.chmod(str(tmpdir / "test2"), 0)
-
-    with patch("gns3server.modules.IOU.get_images_directory", return_value=str(tmpdir),):
-        response = server.post("/iou/vms/test2", body="TEST", raw=True)
-        assert response.status == 409
diff --git a/tests/handlers/api/test_qemu.py b/tests/handlers/api/test_qemu.py
index 07073e60..49cbae62 100644
--- a/tests/handlers/api/test_qemu.py
+++ b/tests/handlers/api/test_qemu.py
@@ -263,9 +263,9 @@ def test_upload_vm_forbiden_location(server, tmpdir):
 
 
 def test_upload_vm_permission_denied(server, tmpdir):
-    with open(str(tmpdir / "test2"), "w+") as f:
+    with open(str(tmpdir / "test2.tmp"), "w+") as f:
         f.write("")
-    os.chmod(str(tmpdir / "test2"), 0)
+    os.chmod(str(tmpdir / "test2.tmp"), 0)
 
     with patch("gns3server.modules.Qemu.get_images_directory", return_value=str(tmpdir),):
         response = server.post("/qemu/vms/test2", body="TEST", raw=True)