diff --git a/Server/Core/Commands/ConnectionHandler.cs b/Server/Core/Commands/ConnectionHandler.cs
index fa903686..a1800c82 100644
--- a/Server/Core/Commands/ConnectionHandler.cs
+++ b/Server/Core/Commands/ConnectionHandler.cs
@@ -30,13 +30,10 @@ namespace xServer.Core.Commands
                 client.Value.PCName = packet.PCName;
 
                 string userAtPc = string.Format("{0}@{1}", client.Value.Username, client.Value.PCName);
-                char[] illegal = Path.GetInvalidPathChars().Union(Path.GetInvalidFileNameChars()).ToArray();
-                bool containsIllegalChar = userAtPc.Count(c => illegal.Contains(c)) > 0;
 
-                if (!containsIllegalChar)
-                    client.Value.DownloadDirectory = Path.Combine(Application.StartupPath, "Clients\\" + userAtPc + "\\");
-                else
-                    client.Value.DownloadDirectory = Path.Combine(Application.StartupPath, "Clients\\" + client.EndPoint.Address.ToString() + "\\");
+                client.Value.DownloadDirectory = (!Helper.Helper.CheckPathForIllegalChars(userAtPc)) ?
+                    Path.Combine(Application.StartupPath, "Clients\\" + userAtPc + "\\") :
+                    Path.Combine(Application.StartupPath, "Clients\\" + client.EndPoint.Address.ToString() + "\\");
 
                 if (!FrmMain.Instance.ListenServer.AllTimeConnectedClients.ContainsKey(client.Value.Id))
                     FrmMain.Instance.ListenServer.AllTimeConnectedClients.Add(client.Value.Id, DateTime.Now);
diff --git a/Server/Core/Helper/Helper.cs b/Server/Core/Helper/Helper.cs
index 9edaec8e..1d6b4e8f 100644
--- a/Server/Core/Helper/Helper.cs
+++ b/Server/Core/Helper/Helper.cs
@@ -1,4 +1,6 @@
 using System;
+using System.IO;
+using System.Linq;
 using System.Text;
 
 namespace xServer.Core.Helper
@@ -8,6 +10,12 @@ namespace xServer.Core.Helper
         private const string CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
         private static readonly Random _rnd = new Random(Environment.TickCount);
         private static readonly string[] _sizes = {"B", "KB", "MB", "GB"};
+        private static readonly char[] _illegalChars = Path.GetInvalidPathChars().Union(Path.GetInvalidFileNameChars()).ToArray();
+
+        public static bool CheckPathForIllegalChars(string path)
+        {
+            return path.Any(c => _illegalChars.Contains(c));
+        }
 
         public static string GetRandomFilename(int length, string extension)
         {
diff --git a/Server/Forms/FrmAddToAutostart.cs b/Server/Forms/FrmAddToAutostart.cs
index ce7eebbc..f8947866 100644
--- a/Server/Forms/FrmAddToAutostart.cs
+++ b/Server/Forms/FrmAddToAutostart.cs
@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Windows.Forms;
+using xServer.Core.Helper;
 using xServer.Core.Misc;
 
 namespace xServer.Forms
@@ -52,16 +53,14 @@ namespace xServer.Forms
 
         private void txtName_KeyPress(object sender, KeyPressEventArgs e)
         {
-            string illegal = new string(Path.GetInvalidPathChars()) + new string(Path.GetInvalidFileNameChars());
-            if ((e.KeyChar == '\\' || illegal.Contains(e.KeyChar.ToString())) && !char.IsControl(e.KeyChar))
-                e.Handled = true;
+            e.Handled = ((e.KeyChar == '\\' || Helper.CheckPathForIllegalChars(e.KeyChar.ToString())) &&
+                         !char.IsControl(e.KeyChar));
         }
 
         private void txtPath_KeyPress(object sender, KeyPressEventArgs e)
         {
-            string illegal = new string(Path.GetInvalidPathChars()) + new string(Path.GetInvalidFileNameChars());
-            if ((e.KeyChar == '\\' || illegal.Contains(e.KeyChar.ToString())) && !char.IsControl(e.KeyChar))
-                e.Handled = true;
+            e.Handled = ((e.KeyChar == '\\' || Helper.CheckPathForIllegalChars(e.KeyChar.ToString())) &&
+                         !char.IsControl(e.KeyChar));
         }
     }
 }
\ No newline at end of file
diff --git a/Server/Forms/FrmBuilder.cs b/Server/Forms/FrmBuilder.cs
index 29f095ef..ba35e40c 100644
--- a/Server/Forms/FrmBuilder.cs
+++ b/Server/Forms/FrmBuilder.cs
@@ -130,8 +130,7 @@ namespace xServer.Forms
 
         private void txtPort_KeyPress(object sender, KeyPressEventArgs e)
         {
-            if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
-                e.Handled = true;
+            e.Handled = (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar));
         }
 
         private void txtDelay_KeyPress(object sender, KeyPressEventArgs e)
@@ -141,16 +140,14 @@ namespace xServer.Forms
 
         private void txtInstallname_KeyPress(object sender, KeyPressEventArgs e)
         {
-            char[] illegal = Path.GetInvalidPathChars().Union(Path.GetInvalidFileNameChars()).ToArray();
-
-            e.Handled = ((e.KeyChar == '\\' || illegal.Any(illegalChar => (illegalChar == e.KeyChar))) && !char.IsControl(e.KeyChar));
+            e.Handled = ((e.KeyChar == '\\' || Helper.CheckPathForIllegalChars(e.KeyChar.ToString())) &&
+                         !char.IsControl(e.KeyChar));
         }
 
         private void txtInstallsub_KeyPress(object sender, KeyPressEventArgs e)
         {
-            char[] illegal = Path.GetInvalidPathChars().Union(Path.GetInvalidFileNameChars()).ToArray();
-
-            e.Handled = ((e.KeyChar == '\\' || illegal.Any(illegalChar => (illegalChar == e.KeyChar))) && !char.IsControl(e.KeyChar));
+            e.Handled = ((e.KeyChar == '\\' || Helper.CheckPathForIllegalChars(e.KeyChar.ToString())) &&
+                         !char.IsControl(e.KeyChar));
         }
 
         private void btnMutex_Click(object sender, EventArgs e)