diff --git a/Source/Contents/MessageTable.cpp b/Source/Contents/MessageTable.cpp
index c20d7d2d..82ffb411 100644
--- a/Source/Contents/MessageTable.cpp
+++ b/Source/Contents/MessageTable.cpp
@@ -14,7 +14,7 @@
 
 // STATIC: 0x016D5780
 // GLOBAL: gl_24382
-std::unordered_map<int, std::string> g_messageStrings;
+std::unordered_map<int, std::string, MessageIdHash> g_messageStrings;
 
 // GLOBAL: gl_24601
 static CCommonObject g_messageTableObject;
diff --git a/Source/Contents/MessageTable.h b/Source/Contents/MessageTable.h
index 347189a9..15a18a79 100644
--- a/Source/Contents/MessageTable.h
+++ b/Source/Contents/MessageTable.h
@@ -10,7 +10,13 @@ enum MessageId : int {
   MSI_FAILED_ADD_TAB = 1578
 };
 
-extern std::unordered_map<int, std::string> g_messageStrings;
+struct MessageIdHash {
+  std::size_t operator()(int id) const {
+    return static_cast<std::size_t>(id);
+  }
+};
+
+extern std::unordered_map<int, std::string, MessageIdHash> g_messageStrings;
 const char* LookupMessage(int id);
 void InsertMessage(int id, const char* text);
 int FindMessageId(const char* name);