diff --git a/src/ResearchTree/ResearchTree.cpp b/src/ResearchTree/ResearchTree.cpp
index db2dbba..b6ddb3e 100644
--- a/src/ResearchTree/ResearchTree.cpp
+++ b/src/ResearchTree/ResearchTree.cpp
@@ -389,7 +389,7 @@ void ResearchTree::readEngineUnlocks(Containers::ArrayView<Int> engines, Contain
         }
     }
 
-    if(gears == nullptr || engines.size() == 0) {
+    if(gears == nullptr || gears.size() == 0) {
         return;
     }