diff --git a/client/windows/GUIClasses.cpp b/client/windows/GUIClasses.cpp
index e921cdf88..bba9a5d5d 100644
--- a/client/windows/GUIClasses.cpp
+++ b/client/windows/GUIClasses.cpp
@@ -749,6 +749,9 @@ void CExchangeController::moveStack(
 	SlotID sourceSlot)
 {
 	auto creature = source->getCreature(sourceSlot);
+	if(creature == nullptr)
+		return;
+
 	SlotID targetSlot = target->getSlotFor(creature);
 
 	if(targetSlot.validSlot())