diff --git a/worlds/sc2/PoolFilter.py b/worlds/sc2/PoolFilter.py
index 3b7fc94b51b6..6df5442b14b1 100644
--- a/worlds/sc2/PoolFilter.py
+++ b/worlds/sc2/PoolFilter.py
@@ -11,7 +11,7 @@
 from . import ItemNames
 
 # Items with associated upgrades
-UPGRADABLE_ITEMS = {item.parent_item for item in get_full_item_list().values()}
+UPGRADABLE_ITEMS = {item.parent_item for item in get_full_item_list().values() if item.parent_item}
 
 BARRACKS_UNITS = {
     ItemNames.Marine, ItemNames.Medic, ItemNames.Firebat, ItemNames.Marauder,