diff --git a/src/utility/Settings.cpp b/src/utility/Settings.cpp
index d43a7b785..9a9ab1120 100644
--- a/src/utility/Settings.cpp
+++ b/src/utility/Settings.cpp
@@ -137,9 +137,9 @@ void Settings::initDescriptions() {
 		("test-prctl", bpo::value<std::string>(), "name of prctl file")
 		("trafile", bpo::value<std::string>()->required(), "name of the .tra file")
 		("labfile", bpo::value<std::string>()->required(), "name of the .lab file")
-		("prctl", bpo::value<std::string>()->default_value(""), "text file containing prctl formulas")
-		("csl", bpo::value<std::string>()->default_value(""), "text file containing csl formulas")
-		("ltl", bpo::value<std::string>()->default_value(""), "text file containing ltl formulas")
+		("prctl", bpo::value<std::string>(), "text file containing prctl formulas")
+		("csl", bpo::value<std::string>(), "text file containing csl formulas")
+		("ltl", bpo::value<std::string>(), "text file containing ltl formulas")
 		("transrew", bpo::value<std::string>()->default_value(""), "name of transition reward file")
 		("staterew", bpo::value<std::string>()->default_value(""), "name of state reward file")
 		("fix-deadlocks", "insert self-loops for states without outgoing transitions")
diff --git a/test/functional/die/testFormulas.prctl b/test/functional/die/testFormulas.prctl
new file mode 100644
index 000000000..8deea6c43
--- /dev/null
+++ b/test/functional/die/testFormulas.prctl
@@ -0,0 +1,4 @@
+P=? [ F one ]
+P=? [ F two ]
+P=? [ F three ]
+R=? [ F done ]