diff --git a/.gitignore b/.gitignore
index fdda839..8fac6a7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,5 +6,5 @@ build
 bin/
 .idea
 .project
-data.csv
+export
 .vscode
\ No newline at end of file
diff --git a/src/main/java/fr/ntr/AccessPoint.java b/src/main/java/fr/ntr/AccessPoint.java
index cca0bd4..c8955c7 100644
--- a/src/main/java/fr/ntr/AccessPoint.java
+++ b/src/main/java/fr/ntr/AccessPoint.java
@@ -1,11 +1,10 @@
 package fr.ntr;
 
-import java.io.FileNotFoundException;
+import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
 
@@ -56,11 +55,12 @@ public class AccessPoint {
      */
     public void startSimulation(int duration) {
         try{
-            Files.deleteIfExists(Paths.get("data.csv"));
-            this.outputDataFile = new FileOutputStream("data.csv", true);
+            Files.deleteIfExists(Paths.get("export", this.users.size() + ".csv"));
+            new File("export").mkdir();
+            this.outputDataFile = new FileOutputStream("export" + File.separator + this.users.size() + ".csv", true);
             outputDataFile.write("tick;x;y;user;bandwidth;\n".getBytes());
-        }catch(IOException e){
-            System.err.println("Cannot create the output file");
+        } catch(IOException e) {
+            System.err.println(e.getClass().getSimpleName() + " : " + e.getMessage());
             System.exit(1);
             return;
         }