diff --git a/cli/src/main/java/de/jplag/cli/JPlagRunner.java b/cli/src/main/java/de/jplag/cli/JPlagRunner.java
index 3346eec62..3dc3b8484 100644
--- a/cli/src/main/java/de/jplag/cli/JPlagRunner.java
+++ b/cli/src/main/java/de/jplag/cli/JPlagRunner.java
@@ -40,6 +40,10 @@ public static JPlagResult runJPlag(JPlagOptions options) throws ExitException {
      * @throws IOException If the internal server throws an exception
      */
     public static void runInternalServer(File zipFile, int port) throws IOException {
+        if (!ReportViewer.hasCompiledViewer()) {
+            logger.warn("The report viewer is not available. Check whether you compiled JPlag with the report viewer.");
+            return;
+        }
         ReportViewer reportViewer = new ReportViewer(zipFile, port);
         int actualPort = reportViewer.start();
         logger.info("ReportViewer started on port http://localhost:{}", actualPort);
diff --git a/cli/src/main/java/de/jplag/cli/server/ReportViewer.java b/cli/src/main/java/de/jplag/cli/server/ReportViewer.java
index 2f5b83cbd..7f4e5c471 100644
--- a/cli/src/main/java/de/jplag/cli/server/ReportViewer.java
+++ b/cli/src/main/java/de/jplag/cli/server/ReportViewer.java
@@ -138,4 +138,8 @@ public void handle(HttpExchange exchange) throws IOException {
     RoutingTree getRoutingTree() {
         return routingTree;
     }
+
+    public static boolean hasCompiledViewer() {
+        return ResponseData.fromResourceUrl("/" + REPORT_VIEWER_RESOURCE_PREFIX + "/index.html") != null;
+    }
 }