diff --git a/main.cpp b/main.cpp
index de9c531..e61c425 100644
--- a/main.cpp
+++ b/main.cpp
@@ -14,6 +14,7 @@
 #include <cmath>
 #include <thread>
 #include <fstream>
+#include <algorithm>
 
 // POSIX
 #include <getopt.h>
@@ -130,10 +131,10 @@ int main(int argc, const char * argv[]) {
                     throw std::runtime_error("unrecognized option");
             }
         }
+        std::vector<std::string> names {sc::plugin<ScreensaverPlugin>::names()};
         if (optind == argc) {
             // here when no file args
             if (random_saver) {
-                std::vector<std::string> names {sc::plugin<ScreensaverPlugin>::names()};
                 saver_name = sc::random::choice(names);
             } else {
                 saver_name = "Default";
@@ -146,6 +147,11 @@ int main(int argc, const char * argv[]) {
                 if (random_saver) {
                     std::cerr << "screensaver: warning: -r option overridden by file arg\n";
                 }
+                auto it = std::find(names.begin(), names.end(), saver_name);
+                if (it == names.end()) {
+                    saver_name = "";
+                    throw std::out_of_range(saver_name);
+                }
                 break; // only first one used
             } catch (const std::runtime_error& ex) {
                 std::cerr << "screensaver: " << ex.what() << '\n';