diff --git a/src/KeyKeeper/PasswordStore/PassStoreFileAccessor.cs b/src/KeyKeeper/PasswordStore/PassStoreFileAccessor.cs
index 8169c34..61ddb4c 100644
--- a/src/KeyKeeper/PasswordStore/PassStoreFileAccessor.cs
+++ b/src/KeyKeeper/PasswordStore/PassStoreFileAccessor.cs
@@ -63,8 +63,8 @@ public class PassStoreFileAccessor : IPassStore
         file.Seek((file.Position + 4096 - 1) / 4096 * 4096, SeekOrigin.Begin);
 
         key.Salt = hdr.PreSalt;
-        this.key = hdr.KdfInfo.GetKdf().Derive(key, 32);
-        using OuterEncryptionReader cryptoReader = new(file, this.key, ((OuterAesHeader)hdr.OuterCryptoHeader).InitVector);
+        byte[] masterKey = hdr.KdfInfo.GetKdf().Derive(key, 32);
+        using OuterEncryptionReader cryptoReader = new(file, masterKey, ((OuterAesHeader)hdr.OuterCryptoHeader).InitVector);
         using BinaryReader rd = new(cryptoReader);
 
         {
@@ -103,6 +103,7 @@ public class PassStoreFileAccessor : IPassStore
                 throw PassStoreFileException.UnexpectedEndOfFile;
             }
         }
+        this.key = masterKey;
     }
 
     public void Lock()
diff --git a/src/KeyKeeper/RepositoryWindow.axaml b/src/KeyKeeper/RepositoryWindow.axaml
index 849cd20..eb57a79 100644
--- a/src/KeyKeeper/RepositoryWindow.axaml
+++ b/src/KeyKeeper/RepositoryWindow.axaml
@@ -3,6 +3,7 @@
         xmlns:vm="using:KeyKeeper.ViewModels"
         x:Class="KeyKeeper.RepositoryWindow"
         Title="KeyKeeper - Хранилище паролей"
+        CanResize="False"
         Width="800"
         Height="600"
         Background="White"
@@ -13,7 +14,7 @@
                 <Grid>
                     <!-- Синий левый край -->
                     <Border Width="200" 
-                            Background="#2328C4" 
+                            Background="#2328C4"
                             HorizontalAlignment="Left" 
                             VerticalAlignment="Stretch"/>
                     <StackPanel Margin="20" HorizontalAlignment="Left">
@@ -42,8 +43,7 @@
 
                         </Border>
                         <!-- Save Passwords -->
-                        <Button Content="Save Passwords" 
-                                Width="120"
+                        <Button Content="Save Passwords"
                                 Height="30"
                                 Foreground="White"
                                 HorizontalAlignment="Left"
diff --git a/src/KeyKeeper/RepositoryWindow.axaml.cs b/src/KeyKeeper/RepositoryWindow.axaml.cs
index e8cd27c..0cf51a7 100644
--- a/src/KeyKeeper/RepositoryWindow.axaml.cs
+++ b/src/KeyKeeper/RepositoryWindow.axaml.cs
@@ -1,13 +1,20 @@
 using System;
 using Avalonia.Controls;
+using KeyKeeper.ViewModels;
+using KeyKeeper.Views;
 
 namespace KeyKeeper;
 
 public partial class RepositoryWindow: Window
 {
-    public RepositoryWindow()
+    public RepositoryWindow(RepositoryWindowViewModel model)
     {
         InitializeComponent();
+        DataContext = model;
+        model.ShowErrorPopup = async (string message) =>
+        {
+            await new ErrorDialog(message).ShowDialog(this);
+        };
     }
 
     protected override void OnOpened(EventArgs e)
diff --git a/src/KeyKeeper/ViewModels/LockedRepositoryViewModel.cs b/src/KeyKeeper/ViewModels/LockedRepositoryViewModel.cs
index 2c57b0e..11745f2 100644
--- a/src/KeyKeeper/ViewModels/LockedRepositoryViewModel.cs
+++ b/src/KeyKeeper/ViewModels/LockedRepositoryViewModel.cs
@@ -10,7 +10,7 @@ public partial class LockedRepositoryViewModel : ViewModelBase
 {
     RepositoryWindowViewModel parent;
     private IPassStore passStore;
-    private string password;
+    private string password = "";
 
     public LockedRepositoryViewModel(IPassStore store, RepositoryWindowViewModel parent)
     {
@@ -25,7 +25,7 @@ public partial class LockedRepositoryViewModel : ViewModelBase
     }
 
     [RelayCommand]
-    public void TryUnlock()
+    public async Task TryUnlock()
     {
         try
         {
@@ -33,12 +33,28 @@ public partial class LockedRepositoryViewModel : ViewModelBase
             parent.UpdateLockStatus();
         } catch (PassStoreFileException e)
         {
-            // TODO
             Console.WriteLine("pass store file exception: " + e.Message);
+            if (e.Message == PassStoreFileException.ContentHMACMismatch.Message ||
+                e.Message == PassStoreFileException.InvalidBeginMarker.Message)
+            {
+                await parent.ShowErrorPopup("Incorrect password or corrupted file");
+            } else if (e.Message == PassStoreFileException.UnexpectedEndOfFile.Message ||
+                       e.Message == PassStoreFileException.IncorrectMagicNumber.Message ||
+                       e.Message == PassStoreFileException.InvalidCryptoHeader.Message ||
+                       e.Message == PassStoreFileException.InvalidPassStoreEntry.Message)
+            {
+                await parent.ShowErrorPopup("Corrupted file");
+            } else if (e.Message == PassStoreFileException.UnsupportedVersion.Message)
+            {
+                await parent.ShowErrorPopup("Unsupported store file version");
+            } else
+            {
+                await parent.ShowErrorPopup("Unknown password store unlock error");
+            }
         } catch (Exception e)
         {
-            // TODO
             Console.WriteLine(e);
+            await parent.ShowErrorPopup("Cannot open the password store file");
         }
     }
 }
\ No newline at end of file
diff --git a/src/KeyKeeper/ViewModels/RepositoryWindowViewModel.cs b/src/KeyKeeper/ViewModels/RepositoryWindowViewModel.cs
index 606c4b9..6626261 100644
--- a/src/KeyKeeper/ViewModels/RepositoryWindowViewModel.cs
+++ b/src/KeyKeeper/ViewModels/RepositoryWindowViewModel.cs
@@ -1,3 +1,5 @@
+using System;
+using System.Threading.Tasks;
 using KeyKeeper.PasswordStore;
 
 namespace KeyKeeper.ViewModels;
@@ -7,6 +9,8 @@ public partial class RepositoryWindowViewModel : ViewModelBase
     private object currentPage;
     private IPassStore passStore;
 
+    public Func<string, Task> ShowErrorPopup;
+
     public object CurrentPage
     {
         get => currentPage;
diff --git a/src/KeyKeeper/Views/ErrorDialog.axaml b/src/KeyKeeper/Views/ErrorDialog.axaml
new file mode 100644
index 0000000..03246d0
--- /dev/null
+++ b/src/KeyKeeper/Views/ErrorDialog.axaml
@@ -0,0 +1,31 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        x:Class="KeyKeeper.Views.ErrorDialog"
+        Width="350" Height="120"
+        Background="White"
+        CanResize="False"
+        Title="Error">
+
+    <Grid Margin="10" RowDefinitions="*,Auto">
+        <TextBlock x:Name="MessageText"
+                   Grid.Row="0"
+                   Foreground="Red"
+                   FontSize="18"
+                   TextWrapping="Wrap" />
+        <Button Grid.Row="1"
+                Content="OK"
+                HorizontalAlignment="Center"
+                Margin="0,10,0,0"
+                Click="Ok_Click"
+                Background="#aaa" />
+        <Grid.Styles>
+            <Style Selector="Button /template/ ContentPresenter">
+                <Setter Property="Foreground" Value="#333" />
+            </Style>
+            <Style Selector="Button:pointerover /template/ ContentPresenter">
+                <Setter Property="Background" Value="#ccc" />
+                <Setter Property="Foreground" Value="#444" />
+            </Style>
+        </Grid.Styles>
+    </Grid>
+</Window>
diff --git a/src/KeyKeeper/Views/ErrorDialog.axaml.cs b/src/KeyKeeper/Views/ErrorDialog.axaml.cs
new file mode 100644
index 0000000..46e9306
--- /dev/null
+++ b/src/KeyKeeper/Views/ErrorDialog.axaml.cs
@@ -0,0 +1,18 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace KeyKeeper.Views;
+
+public partial class ErrorDialog : Window
+{
+    public ErrorDialog(string message)
+    {
+        InitializeComponent();
+        MessageText.Text = message;
+    }
+
+    private void Ok_Click(object sender, RoutedEventArgs e)
+    {
+        Close();
+    }
+}
\ No newline at end of file
diff --git a/src/KeyKeeper/Views/MainWindow.axaml.cs b/src/KeyKeeper/Views/MainWindow.axaml.cs
index 3bf9f0c..679581c 100644
--- a/src/KeyKeeper/Views/MainWindow.axaml.cs
+++ b/src/KeyKeeper/Views/MainWindow.axaml.cs
@@ -82,9 +82,8 @@ namespace KeyKeeper.Views
 
         private void OpenRepositoryWindow(IPassStore store)
         {
-            var repositoryWindow = new RepositoryWindow()
+            var repositoryWindow = new RepositoryWindow(new RepositoryWindowViewModel(store))
             {
-                DataContext = new RepositoryWindowViewModel(store),
                 WindowStartupLocation = WindowStartupLocation.CenterScreen
             };
             repositoryWindow.Closed += (s, e) => this.Show();