diff --git a/Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs b/Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs
index 00f2f406..93620883 100644
--- a/Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs
+++ b/Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs
@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System;
+using System.Threading.Tasks;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Models.Accounts;
@@ -23,6 +24,18 @@ public interface IBaseSynchronizer
     /// <param name="request">Request to queue.</param>
     void QueueRequest(IRequestBase request);
 
+    /// <summary>
+    /// Returns whether there is an in-progress (queued or currently executing) operation for the given mail unique id.
+    /// </summary>
+    /// <param name="mailUniqueId">Mail unique id to check.</param>
+    bool HasPendingOperation(Guid mailUniqueId);
+
+    /// <summary>
+    /// Returns whether there is an in-progress (queued or currently executing) operation for the given calendar item id.
+    /// </summary>
+    /// <param name="calendarItemId">Calendar item id to check.</param>
+    bool HasPendingCalendarOperation(Guid calendarItemId);
+
     /// <summary>
     /// Synchronizes profile information with the server.
     /// Sender name and Profile picture are updated.
diff --git a/Wino.Core/Synchronizers/BaseSynchronizer.cs b/Wino.Core/Synchronizers/BaseSynchronizer.cs
index 500f14f9..5b1637c5 100644
--- a/Wino.Core/Synchronizers/BaseSynchronizer.cs
+++ b/Wino.Core/Synchronizers/BaseSynchronizer.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Net.Http;
 using System.Threading;
@@ -20,6 +21,8 @@ public abstract partial class BaseSynchronizer<TBaseRequest> : ObservableObject,
     protected CancellationToken activeSynchronizationCancellationToken;
 
     protected List<IRequestBase> changeRequestQueue = [];
+    private readonly ConcurrentDictionary<Guid, byte> _pendingMailOperationIds = new();
+    private readonly ConcurrentDictionary<Guid, byte> _pendingCalendarOperationIds = new();
     protected readonly IMessenger Messenger;
     
     public MailAccount Account { get; }
@@ -119,7 +122,47 @@ public abstract partial class BaseSynchronizer<TBaseRequest> : ObservableObject,
     /// Queues a single request to be executed in the next synchronization.
     /// </summary>
     /// <param name="request">Request to execute.</param>
-    public void QueueRequest(IRequestBase request) => changeRequestQueue.Add(request);
+    public void QueueRequest(IRequestBase request)
+    {
+        changeRequestQueue.Add(request);
+        TrackQueuedRequest(request);
+    }
+
+    public bool HasPendingOperation(Guid mailUniqueId) => _pendingMailOperationIds.ContainsKey(mailUniqueId);
+
+    public bool HasPendingCalendarOperation(Guid calendarItemId) => _pendingCalendarOperationIds.ContainsKey(calendarItemId);
+
+    protected void TrackQueuedRequest(IRequestBase request)
+    {
+        if (request is IMailActionRequest mailActionRequest)
+        {
+            _pendingMailOperationIds.TryAdd(mailActionRequest.Item.UniqueId, 0);
+        }
+
+        if (request is ICalendarActionRequest calendarActionRequest)
+        {
+            _pendingCalendarOperationIds.TryAdd(calendarActionRequest.Item.Id, 0);
+        }
+    }
+
+    protected void UntrackProcessedRequest(IRequestBase request)
+    {
+        if (request is IMailActionRequest mailActionRequest)
+        {
+            _pendingMailOperationIds.TryRemove(mailActionRequest.Item.UniqueId, out _);
+        }
+
+        if (request is ICalendarActionRequest calendarActionRequest)
+        {
+            _pendingCalendarOperationIds.TryRemove(calendarActionRequest.Item.Id, out _);
+        }
+    }
+
+    protected void UntrackProcessedRequests(IEnumerable<IRequestBase> requests)
+    {
+        foreach (var request in requests)
+            UntrackProcessedRequest(request);
+    }
 
     /// <summary>
     /// Runs existing queued requests in the queue.
diff --git a/Wino.Core/Synchronizers/WinoSynchronizer.cs b/Wino.Core/Synchronizers/WinoSynchronizer.cs
index bfb3f66f..9375611b 100644
--- a/Wino.Core/Synchronizers/WinoSynchronizer.cs
+++ b/Wino.Core/Synchronizers/WinoSynchronizer.cs
@@ -219,7 +219,14 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
 
                 Console.WriteLine($"Prepared {nativeRequests.Count()} native requests");
 
-                await ExecuteNativeRequestsAsync(nativeRequests, activeSynchronizationCancellationToken).ConfigureAwait(false);
+                try
+                {
+                    await ExecuteNativeRequestsAsync(nativeRequests, activeSynchronizationCancellationToken).ConfigureAwait(false);
+                }
+                finally
+                {
+                    UntrackProcessedRequests(requestCopies);
+                }
 
                 Messenger.Send(new SynchronizationActionsCompleted(Account.Id));
 
@@ -419,7 +426,14 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
 
             Console.WriteLine($"Prepared {nativeRequests.Count()} native calendar requests");
 
-            await ExecuteNativeRequestsAsync(nativeRequests, cancellationToken).ConfigureAwait(false);
+            try
+            {
+                await ExecuteNativeRequestsAsync(nativeRequests, cancellationToken).ConfigureAwait(false);
+            }
+            finally
+            {
+                UntrackProcessedRequests(requestCopies);
+            }
 
             Messenger.Send(new SynchronizationActionsCompleted(Account.Id));
 
diff --git a/Wino.Mail.ViewModels/ComposePageViewModel.cs b/Wino.Mail.ViewModels/ComposePageViewModel.cs
index 4e9eadfb..da962c49 100644
--- a/Wino.Mail.ViewModels/ComposePageViewModel.cs
+++ b/Wino.Mail.ViewModels/ComposePageViewModel.cs
@@ -35,7 +35,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
     // Update is triggered when we leave the page.
     private bool isUpdatingMimeBlocked = false;
 
-    private bool canSendMail => ComposingAccount != null && !IsLocalDraft && CurrentMimeMessage != null;
+    private bool canSendMail => ComposingAccount != null && !IsLocalDraft && CurrentMimeMessage != null && !IsDraftBusy;
 
     [NotifyCanExecuteChangedFor(nameof(DiscardCommand))]
     [NotifyCanExecuteChangedFor(nameof(SendCommand))]
@@ -52,24 +52,29 @@ public partial class ComposePageViewModel : MailBaseViewModel,
     [NotifyPropertyChangedFor(nameof(IsLocalDraft))]
     [NotifyCanExecuteChangedFor(nameof(DiscardCommand))]
     [NotifyCanExecuteChangedFor(nameof(SendCommand))]
-    private MailItemViewModel currentMailDraftItem;
-
-    [ObservableProperty]
-    private bool isImportanceSelected;
-
-    [ObservableProperty]
-    private MessageImportance selectedMessageImportance;
-
-    [ObservableProperty]
-    private bool isCCBCCVisible;
-
-    [ObservableProperty]
-    private string subject;
+    public partial MailItemViewModel CurrentMailDraftItem { get; set; }
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(DiscardCommand))]
     [NotifyCanExecuteChangedFor(nameof(SendCommand))]
-    private MailAccount composingAccount;
+    public partial bool IsDraftBusy { get; set; }
+
+    [ObservableProperty]
+    public partial bool IsImportanceSelected { get; set; }
+
+    [ObservableProperty]
+    public partial MessageImportance SelectedMessageImportance { get; set; }
+
+    [ObservableProperty]
+    public partial bool IsCCBCCVisible { get; set; }
+
+    [ObservableProperty]
+    public partial string Subject { get; set; }
+
+    [ObservableProperty]
+    [NotifyCanExecuteChangedFor(nameof(DiscardCommand))]
+    [NotifyCanExecuteChangedFor(nameof(SendCommand))]
+    public partial MailAccount ComposingAccount { get; set; }
 
     [ObservableProperty]
     public partial List<MailAccountAlias> AvailableAliases { get; set; }
@@ -312,6 +317,8 @@ public partial class ComposePageViewModel : MailBaseViewModel,
                                                                           CurrentMailDraftItem.MailCopy.AssignedAccount.Preferences,
                                                                           base64EncodedMessage);
 
+        IsDraftBusy = true;
+
         await _worker.ExecuteAsync(draftSendPreparationRequest);
     }
 
@@ -430,6 +437,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
         {
             CurrentMailDraftItem = mailItem;
 
+            await UpdatePendingOperationStateAsync();
             await TryPrepareComposeAsync(true);
         }
     }
@@ -446,6 +454,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
 
         // Set the new draft item and prepare it.
         CurrentMailDraftItem = message.MailItemViewModel;
+        await UpdatePendingOperationStateAsync();
         await TryPrepareComposeAsync(true);
     }
 
@@ -500,6 +509,23 @@ public partial class ComposePageViewModel : MailBaseViewModel,
         return true;
     }
 
+    private async Task UpdatePendingOperationStateAsync()
+    {
+        IsDraftBusy = false;
+
+        if (CurrentMailDraftItem?.MailCopy == null || !CurrentMailDraftItem.MailCopy.IsDraft)
+            return;
+
+        var accountId = CurrentMailDraftItem.MailCopy.AssignedAccount?.Id ?? Guid.Empty;
+
+        if (accountId == Guid.Empty)
+            return;
+
+        var synchronizer = await SynchronizationManager.Instance.GetSynchronizerAsync(accountId).ConfigureAwait(false);
+
+        IsDraftBusy = synchronizer?.HasPendingOperation(CurrentMailDraftItem.MailCopy.UniqueId) ?? false;
+    }
+
     private async Task TryPrepareComposeAsync(bool downloadIfNeeded)
     {
         if (CurrentMailDraftItem == null) return;
@@ -674,11 +700,13 @@ public partial class ComposePageViewModel : MailBaseViewModel,
 
         if (updatedMail.UniqueId == CurrentMailDraftItem.MailCopy.UniqueId)
         {
-            await ExecuteUIThread(() =>
+            await ExecuteUIThread(async () =>
             {
                 CurrentMailDraftItem.UpdateFrom(updatedMail);
                 DiscardCommand.NotifyCanExecuteChanged();
                 SendCommand.NotifyCanExecuteChanged();
+
+                await UpdatePendingOperationStateAsync();
             });
         }
     }
diff --git a/Wino.Mail.WinUI/Views/Mail/ComposePage.xaml b/Wino.Mail.WinUI/Views/Mail/ComposePage.xaml
index 29f277ed..45c9b62a 100644
--- a/Wino.Mail.WinUI/Views/Mail/ComposePage.xaml
+++ b/Wino.Mail.WinUI/Views/Mail/ComposePage.xaml
@@ -190,6 +190,14 @@
                             CommandAlignment="Right"
                             IsDynamicOverflowEnabled="True"
                             OverflowButtonAlignment="Left">
+                            <AppBarButton
+                                MinWidth="40"
+                                HorizontalContentAlignment="Center"
+                                VerticalContentAlignment="Center"
+                                Visibility="{x:Bind ViewModel.IsDraftBusy, Mode=OneWay}">
+                                <ProgressRing IsActive="True" />
+                            </AppBarButton>
+
                             <AppBarButton
                                 Width="Auto"
                                 MinWidth="40"