diff --git a/libs/ardour/luaproc.cc b/libs/ardour/luaproc.cc
index ec13efb1bf..bf93e1df67 100644
--- a/libs/ardour/luaproc.cc
+++ b/libs/ardour/luaproc.cc
@@ -1258,7 +1258,7 @@ LuaPluginInfo::load (Session& session)
 
 	try {
 		script = Glib::file_get_contents (path);
-	} catch (Glib::FileError err) {
+	} catch (Glib::FileError const& err) {
 		return PluginPtr ();
 	}
 
diff --git a/libs/ardour/luascripting.cc b/libs/ardour/luascripting.cc
index 1193e08130..e748fb656e 100644
--- a/libs/ardour/luascripting.cc
+++ b/libs/ardour/luascripting.cc
@@ -262,7 +262,7 @@ LuaScripting::scan_script (const std::string &fn, const std::string &sc)
 		try {
 			std::string script = Glib::file_get_contents (fn);
 			sha1_write (&s, (const uint8_t *) script.c_str(), script.size ());
-		} catch (Glib::FileError err) {
+		} catch (Glib::FileError const& err) {
 			return LuaScriptInfoPtr();
 		}
 	}
diff --git a/libs/ardour/session_directory.cc b/libs/ardour/session_directory.cc
index 1f6b991f82..fd90959ac4 100644
--- a/libs/ardour/session_directory.cc
+++ b/libs/ardour/session_directory.cc
@@ -167,7 +167,7 @@ SessionDirectory::sources_root () const
 			PBD::fatal << string_compose (_("The session's interchange dir is tainted.\nThere is more than one folder in '%1'.\nPlease remove extra subdirs to reduce possible filename ambiguties."), sources_root_path) << endmsg;
 			assert (0); // not reached
 		}
-	} catch (Glib::FileError) {
+	} catch (Glib::FileError const&) {
 		;
 	}
 
diff --git a/libs/ardour/test/lua_script_test.cc b/libs/ardour/test/lua_script_test.cc
index a404824d15..d707fdb34e 100644
--- a/libs/ardour/test/lua_script_test.cc
+++ b/libs/ardour/test/lua_script_test.cc
@@ -32,7 +32,7 @@ LuaScriptTest::session_script_test ()
 
 		try {
 			script = Glib::file_get_contents (spi->path);
-		} catch (Glib::FileError e) {
+		} catch (Glib::FileError const& e) {
 			CPPUNIT_FAIL ("Cannot read script file");
 			continue;
 		}
diff --git a/libs/gtkmm2ext/utils.cc b/libs/gtkmm2ext/utils.cc
index aa139981fc..bdb44090c3 100644
--- a/libs/gtkmm2ext/utils.cc
+++ b/libs/gtkmm2ext/utils.cc
@@ -1114,7 +1114,7 @@ Gtkmm2ext::add_volume_shortcuts (Gtk::FileChooser& c)
 			}
 		}
 	}
-	catch (Glib::FileError& e) {
+	catch (Glib::FileError const& e) {
 		std::cerr << "listing /Volumnes failed: " << e.what() << std::endl;
 	}
 #endif
diff --git a/libs/pbd/file_utils.cc b/libs/pbd/file_utils.cc
index 4549e93009..3fc3cdf99e 100644
--- a/libs/pbd/file_utils.cc
+++ b/libs/pbd/file_utils.cc
@@ -127,7 +127,7 @@ run_functor_for_paths (vector<string>& result,
 				}
 			}
 		}
-		catch (Glib::FileError& err)
+		catch (Glib::FileError const& err)
 		{
 			warning << err.what() << endmsg;
 		}