diff --git a/src/storm/settings/Argument.cpp b/src/storm/settings/Argument.cpp
index 555bcdb9d..7e2d64c0b 100644
--- a/src/storm/settings/Argument.cpp
+++ b/src/storm/settings/Argument.cpp
@@ -171,20 +171,28 @@ namespace storm {
             out << std::setw(0) << std::left << "<" << this->getName() << ">";
             if (!this->validators.empty() || this->hasDefaultValue) {
                 out << " (";
+                bool previousEntry = false;
+                if (this->getIsOptional()) {
+                    out << "optional";
+                    previousEntry = true;
+                }
                 if (!this->validators.empty()) {
+                    if (previousEntry) {
+                        out << "; ";
+                    }
                     for (uint64_t i = 0; i < this->validators.size(); ++i) {
                         out << this->validators[i]->toString();
                         if (i + 1 < this->validators.size()) {
                             out << ", ";
                         }
                     }
-                    
-                    if (this->hasDefaultValue) {
-                        out << "; ";
-                    }
+                    previousEntry = true;
                 }
                 
                 if (this->hasDefaultValue) {
+                    if (previousEntry) {
+                        out << "; ";
+                    }
                     out << "default: ";
                     printValue(out, defaultValue);
                 }
diff --git a/src/storm/settings/SettingsManager.cpp b/src/storm/settings/SettingsManager.cpp
index 7088f924e..058d92d99 100644
--- a/src/storm/settings/SettingsManager.cpp
+++ b/src/storm/settings/SettingsManager.cpp
@@ -491,7 +491,7 @@ namespace storm {
             // In case there are optional arguments that were not set, we set them to their default value.
             for (uint_fast64_t i = argumentCache.size(); i < option->getArgumentCount(); ++i) {
                 ArgumentBase& argument = option->getArgument(i);
-                STORM_LOG_THROW(argument.getHasDefaultValue() || argument.getIsOptional(), storm::exceptions::OptionParserException, "Non-optional argument <" << argument.getName() << "> of option:\n" << *option);
+                STORM_LOG_THROW(argument.getIsOptional(), storm::exceptions::OptionParserException, "Non-optional argument <" << argument.getName() << "> of option:\n" << *option);
                 argument.setFromDefaultValue();
             }