diff --git a/bin/debugger.cpp b/bin/debugger.cpp
index a9d5b10..26e9eee 100644
--- a/bin/debugger.cpp
+++ b/bin/debugger.cpp
@@ -1252,13 +1252,13 @@ void Shell()
 
 	// load the error code to error mnemonic
 	ErrorTableInvert.reserve(ErrorTable.size());
-	for (const auto kv : ErrorTable) {
+	for (const auto &kv : ErrorTable) {
 		ErrorTableInvert.emplace(std::make_pair(kv.second, kv.first));
 	}
 
 	// address to function name.
 	SymbolTableInvert.reserve(SymbolTable.size());
-	for (const auto kv : SymbolTable) {
+	for (const auto &kv : SymbolTable) {
 		SymbolTableInvert.emplace(std::make_pair(kv.second.first, kv.first));
 	}
 
diff --git a/toolbox/mm.cpp b/toolbox/mm.cpp
index 7f8daa9..cfba0a1 100644
--- a/toolbox/mm.cpp
+++ b/toolbox/mm.cpp
@@ -154,7 +154,7 @@ namespace MM
 			}
 
 			// 2. check if it's contained in a pointer
-			for (const auto kv : PtrMap)
+			for (const auto &kv : PtrMap)
 			{
 				if (address < kv.first) continue;
 				if (address >= kv.first + kv.second) continue;
@@ -184,7 +184,7 @@ namespace MM
 
 			// 3. check if the address is within a handle.
 			{
-				for (const auto kv : HandleMap)
+				for (const auto &kv : HandleMap)
 				{
 					const HandleInfo &info = kv.second;
 
@@ -1145,7 +1145,7 @@ namespace MM
 		Log("%04x RecoverHandle(%08x)\n", trap, p);
 
 		uint16_t error = MacOS::memBCErr;
-		for (const auto kv : HandleMap)
+		for (const auto &kv : HandleMap)
 		{
 			const HandleInfo &info = kv.second;