diff --git a/rpcs3/rpcs3qt/memory_viewer_panel.cpp b/rpcs3/rpcs3qt/memory_viewer_panel.cpp
index 9e9815385b..392b3e0385 100644
--- a/rpcs3/rpcs3qt/memory_viewer_panel.cpp
+++ b/rpcs3/rpcs3qt/memory_viewer_panel.cpp
@@ -604,8 +604,9 @@ memory_viewer_panel::memory_viewer_panel(QWidget* parent, std::shared_ptr<CPUDis
 	{
 		if (auto fxo = g_fxo->try_get<memory_viewer_fxo>())
 		{
-			if (this == fxo->last_opened[m_type])
-				fxo->last_opened.erase(m_type);
+			auto it = fxo->last_opened.find(m_type);
+			if (it != fxo->last_opened.end() && it->second == this)
+				fxo->last_opened.erase(it);
 		}
 	});
 }