diff --git a/src/storm/modelchecker/parametric/ParameterLifting.cpp b/src/storm/modelchecker/parametric/ParameterLifting.cpp
index a0ab01eeb..01e44a830 100644
--- a/src/storm/modelchecker/parametric/ParameterLifting.cpp
+++ b/src/storm/modelchecker/parametric/ParameterLifting.cpp
@@ -222,14 +222,15 @@ namespace storm {
                 
                 std::stringstream stream;
                 
-                uint_fast64_t const size = 64;
+                uint_fast64_t const sizeX = 128;
+                uint_fast64_t const sizeY = 64;
                 
                 stream << "Parameter lifting result (visualization):" << std::endl;
                 stream << " \t x-axis: " << x << "  \t y-axis: " << y << "  \t S=safe, [ ]=unsafe, -=ambiguous " << std::endl;
-                for (uint_fast64_t i = 0; i < 2*size+2; ++i) stream << "#"; stream << std::endl;
+                for (uint_fast64_t i = 0; i < sizeX+2; ++i) stream << "#"; stream << std::endl;
                 
-                ValueType deltaX = (parameterSpace.getUpperBoundary(x) - parameterSpace.getLowerBoundary(x)) / storm::utility::convertNumber<ValueType>(size);
-                ValueType deltaY = (parameterSpace.getUpperBoundary(y) - parameterSpace.getLowerBoundary(y)) / storm::utility::convertNumber<ValueType>(size);
+                ValueType deltaX = (parameterSpace.getUpperBoundary(x) - parameterSpace.getLowerBoundary(x)) / storm::utility::convertNumber<ValueType>(sizeX);
+                ValueType deltaY = (parameterSpace.getUpperBoundary(y) - parameterSpace.getLowerBoundary(y)) / storm::utility::convertNumber<ValueType>(sizeY);
                 ValueType printedRegionArea = deltaX * deltaY;
                 for (ValueType yUpper = parameterSpace.getUpperBoundary(y); yUpper != parameterSpace.getLowerBoundary(y); yUpper -= deltaY) {
                     ValueType yLower = yUpper - deltaY;
@@ -257,16 +258,16 @@ namespace storm {
                             }
                         }
                         if (currRegionComplete && currRegionSafe && !currRegionUnSafe) {
-                            stream << "SS";
+                            stream << "S";
                         } else if (currRegionComplete && currRegionUnSafe && !currRegionSafe) {
-                            stream << "  ";
+                            stream << " ";
                         } else {
-                            stream << "--";
+                            stream << "-";
                         }
                     }
                     stream << "#" << std::endl;
                 }
-                for (uint_fast64_t i = 0; i < 2*size+2; ++i) stream << "#"; stream << std::endl;
+                for (uint_fast64_t i = 0; i < sizeX+2; ++i) stream << "#"; stream << std::endl;
                 return stream.str();
             }
         
diff --git a/src/storm/settings/modules/ParametricSettings.cpp b/src/storm/settings/modules/ParametricSettings.cpp
index 844f214c3..76ca0adc9 100644
--- a/src/storm/settings/modules/ParametricSettings.cpp
+++ b/src/storm/settings/modules/ParametricSettings.cpp
@@ -24,9 +24,9 @@ namespace storm {
                 this->addOption(storm::settings::OptionBuilder(moduleName, encodeSmt2StrategyOptionName, true, "Set the smt2 encoding strategy.")
                                 .addArgument(storm::settings::ArgumentBuilder::createStringArgument("strategy", "the used strategy").build()).build());
                 this->addOption(storm::settings::OptionBuilder(moduleName, exportSmt2DestinationPathOptionName, true, "A path to a file where the result should be saved.")
-                                .addArgument(storm::settings::ArgumentBuilder::createStringArgument("path", "the location.").build()).build());
+                                .addArgument(storm::settings::ArgumentBuilder::createStringArgument("path", "the location.").addValidatorString(ArgumentValidatorFactory::createWritableFileValidator()).build()).build());
                 this->addOption(storm::settings::OptionBuilder(moduleName, exportResultDestinationPathOptionName, true, "A path to a file where the smt2 encoding should be saved.")
-                                .addArgument(storm::settings::ArgumentBuilder::createStringArgument("path", "the location.").build()).build());
+                                .addArgument(storm::settings::ArgumentBuilder::createStringArgument("path", "the location.").addValidatorString(ArgumentValidatorFactory::createWritableFileValidator()).build()).build());
                 this->addOption(storm::settings::OptionBuilder(moduleName, parameterSpaceOptionName, true, "Sets the considered parameter-space (i.e., the initial region) for parameter lifting.")
                                 .addArgument(storm::settings::ArgumentBuilder::createStringArgument("region", "The parameter-space (given in format a<=x<=b,c<=y<=d).").build()).build());
                 this->addOption(storm::settings::OptionBuilder(moduleName, refinementThresholdOptionName, true, "Parameter space refinement converges if the fraction of unknown area falls below this threshold.")