diff --git a/libultraship/libultraship/ResourceMgr.cpp b/libultraship/libultraship/ResourceMgr.cpp
index 6c6a0175f..4ca77708a 100644
--- a/libultraship/libultraship/ResourceMgr.cpp
+++ b/libultraship/libultraship/ResourceMgr.cpp
@@ -293,7 +293,7 @@ namespace Ship {
 		return LoadedList;
 	}
 
-	std::shared_ptr<std::vector<std::shared_ptr<Resource>>> ResourceMgr::DirtyDirectory(std::string& SearchMask) {
+	std::shared_ptr<std::vector<std::shared_ptr<Resource>>> ResourceMgr::DirtyDirectory(const std::string& SearchMask) {
 		auto PromiseList = CacheDirectoryAsync(SearchMask);
 		auto LoadedList = std::make_shared<std::vector<std::shared_ptr<Resource>>>();
 
diff --git a/libultraship/libultraship/ResourceMgr.h b/libultraship/libultraship/ResourceMgr.h
index 404933ceb..e0b0c07cf 100644
--- a/libultraship/libultraship/ResourceMgr.h
+++ b/libultraship/libultraship/ResourceMgr.h
@@ -40,7 +40,7 @@ namespace Ship {
 		std::variant<std::shared_ptr<Resource>, std::shared_ptr<ResourcePromise>> LoadResourceAsync(const char* FilePath);
 		std::shared_ptr<std::vector<std::shared_ptr<Resource>>> CacheDirectory(const std::string& SearchMask);
 		std::shared_ptr<std::vector<std::shared_ptr<ResourcePromise>>> CacheDirectoryAsync(const std::string& SearchMask);
-		std::shared_ptr<std::vector<std::shared_ptr<Resource>>> DirtyDirectory(std::string& SearchMask);
+		std::shared_ptr<std::vector<std::shared_ptr<Resource>>> DirtyDirectory(const std::string& SearchMask);
 		std::shared_ptr<std::vector<std::string>> ListFiles(std::string SearchMask);
 
 	protected: