diff --git a/src/myutil/FileUtils.java b/src/myutil/FileUtils.java
index ecae482a39dfdf2bdfcbf6cf70d6d534abc2f72d..fbe24343a3bbf34b46abcc0e0dcc2558d8ea534b 100755
--- a/src/myutil/FileUtils.java
+++ b/src/myutil/FileUtils.java
@@ -46,7 +46,7 @@
 package myutil;
 
 import java.io.*;
-
+import java.nio.file.*;
 
 
 public class FileUtils {
@@ -78,9 +78,14 @@ public class FileUtils {
         return ext;
     }
 
+
+    public static boolean checkPath(String path) {
+	return new File(path).isDirectory();
+    }
+
     public static boolean checkFileForSave(File file) throws FileException {
-   //     boolean ok = true;
-    //    String pb = "";
+        //     boolean ok = true;
+        //    String pb = "";
 
         if (file == null) {
             return false;
@@ -238,8 +243,8 @@ public class FileUtils {
     }
 
     public static void saveFile(String name, String data) throws FileException {
-	 File f = new File(name);
-	 saveFile(f, data);
+        File f = new File(name);
+        saveFile(f, data);
     }
 
 
diff --git a/src/ui/window/JDialogProverifVerification.java b/src/ui/window/JDialogProverifVerification.java
index da0d72a9572a980a7a3e1971082c812783f4a2b1..75e6a890d070ed37a60e01fb2610e1fbf8a47b72 100644
--- a/src/ui/window/JDialogProverifVerification.java
+++ b/src/ui/window/JDialogProverifVerification.java
@@ -383,7 +383,14 @@ public class JDialogProverifVerification extends javax.swing.JDialog implements
 
                 if (pathCode.isEmpty()){
                     pathCode="pvspec";
-                }
+                } else {
+		    if (!FileUtils.checkPath(pathCode)) {
+			jta.append("Error: invalid directory: " + pathCode + "\n");
+			mode =      STOPPED;
+			setButtons();
+			return;
+		    }
+		}
 
                 testFile = new File(pathCode);