diff --git a/libs/ardour/filesystem_paths.cc b/libs/ardour/filesystem_paths.cc
index 73bfaff137..bea0e330b9 100644
--- a/libs/ardour/filesystem_paths.cc
+++ b/libs/ardour/filesystem_paths.cc
@@ -86,11 +86,14 @@ user_config_directory ()
 std::string
 ardour_dll_directory ()
 {
-	std::string s = Glib::getenv("ARDOUR_DLL_PATH");
+	static std::string s;
+
 	if (s.empty()) {
-		std::cerr << _("ARDOUR_DLL_PATH not set in environment - exiting\n");
-		::exit (1);
-	}	
+			s = Glib::getenv("ARDOUR_DLL_PATH");
+			std::cerr << _("ARDOUR_DLL_PATH not set in environment - exiting\n");
+			::exit (1);
+		}
+
 	return s;
 }