diff --git a/gogdl/dl/managers/v2.py b/gogdl/dl/managers/v2.py
index f5a082b..8d3bc46 100644
--- a/gogdl/dl/managers/v2.py
+++ b/gogdl/dl/managers/v2.py
@@ -64,8 +64,8 @@ def get_download_size(self):
         for depot in repository["depots"]:
             if depot["dependencyId"] in self.manifest.dependencies_ids:
                 if not depot["executable"]["path"].startswith("__redist"):
-                    size_data[self.game_id]['*']["download_size"] += depot["compressedSize"]
-                    size_data[self.game_id]['*']["disk_size"] += depot["size"]
+                    size_data[self.game_id]['*']["download_size"] += depot["compressedSize"] or 0
+                    size_data[self.game_id]['*']["disk_size"] += depot["size"] or 0
 
         available_branches = set([build["branch"] for build in self.builds["items"] if build["branch"]])
         available_branches_list = [None] + list(available_branches)