diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SendAs/FeatureSendAs.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SendAs/FeatureSendAs.cs
index 446ccf2..49cb32f 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SendAs/FeatureSendAs.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SendAs/FeatureSendAs.cs
@@ -27,6 +27,7 @@ using Acacia.ZPush.API.SharedFolders;
 using static Acacia.DebugOptions;
 using Acacia.Features.GAB;
 using Acacia.Features.SyncState;
+using System.Windows.Forms;
 
 namespace Acacia.Features.SendAs
 {
@@ -108,7 +109,6 @@ namespace Acacia.Features.SendAs
             Logger.Instance.Trace(this, "Responding to mail, checking");
             using (IStore store = mail.GetStore())
             {
-                /*
                 ZPushAccount zpush = Watcher.Accounts.GetAccount(store);
                 Logger.Instance.Trace(this, "Checking ZPush: {0}", zpush);
                 if (zpush == null)
@@ -127,7 +127,7 @@ namespace Acacia.Features.SendAs
                     {
                         response.SetSender(address);
                     }
-                }*/
+                }
             }
         }
 
@@ -159,11 +159,57 @@ namespace Acacia.Features.SendAs
 
         #region Address resolving
 
+        private IRecipient FindSendAsSender(ZPushAccount zpush, IFolder folder)
+        {
+            SyncId syncId = folder.SyncId;
+            if (syncId != null)
+            {
+                string address = zpush.GetSendAsAddress(syncId);
+                if (address == null)
+                {
+                    // Check if it should have an address
+                    SharedFolder shared = _sharedFolders?.GetSharedFolder(folder);
+                    if (shared?.FlagSendAsOwner == true)
+                    {
+                        // See if we can get it now
+                        address = FindSendAsAddress(zpush, shared);
+
+                        if (address == null)
+                        {
+                            // Should have it, error
+                            MessageBox.Show(ThisAddIn.Instance.Window,
+                                               Properties.Resources.SharedFolders_SendAsFailed_Label,
+                                               Properties.Resources.SharedFolders_SendAsFailed_Title,
+                                               MessageBoxButtons.OK,
+                                               MessageBoxIcon.Error
+                                           );
+                        }
+                        else
+                        {
+
+                        }
+                    }
+                }
+
+                if (address != null)
+                {
+                    IRecipient resolved = ThisAddIn.Instance.ResolveRecipient(address);
+                    if (resolved != null)
+                        return resolved;
+                }
+            }
+            return null;
+        }
+
         public string FindSendAsAddress(ZPushAccount zpush, SharedFolder folder)
         {
             string address = folder.SendAsAddress;
             if (!string.IsNullOrWhiteSpace(address))
+            {
+                // Make sure it's in the registry
+                StoreSyncIdAddress(zpush, folder);
                 return address;
+            }
 
             // Check the registry
             string addressSync = zpush.GetSendAsAddress(folder.SyncId);
@@ -171,20 +217,23 @@ namespace Acacia.Features.SendAs
             // If we have no address on sync id, or it differs from the one on backend id, backend id wins, as that's the one set by the dialog
             if (string.IsNullOrWhiteSpace(addressSync) || !addressSync.Equals(addressBackend))
             {
-                address = addressBackend;
+                folder.SendAsAddress = address = addressBackend;
                 // Resolved now, store on sync id
-                if (folder.SyncId.IsCustom)
-                    zpush.SetSendAsAddress(folder.SyncId, address);
+                StoreSyncIdAddress(zpush, folder);
             }
             else address = addressSync;
 
             return address;
         }
 
+        private void StoreSyncIdAddress(ZPushAccount zpush, SharedFolder folder)
+        {
+            if (!string.IsNullOrWhiteSpace(folder.SyncId?.ToString()) && !folder.SyncId.Equals(folder.BackendId))
+                zpush.SetSendAsAddress(folder.SyncId, folder.SendAsAddress);
+        }
+
         internal void UpdateSendAsAddresses(ZPushAccount zpush, ICollection<SharedFolder> shares)
         {
-            SyncState.SyncState state = ThisAddIn.Instance.GetFeature<FeatureSyncState>()?.GetSyncState(zpush);
-
             foreach (SharedFolder folder in shares)
             {
                 if (!folder.FlagSendAsOwner)
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SharedFolders/FeatureSharedFolders.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SharedFolders/FeatureSharedFolders.cs
index 6c64d86..7b0e709 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SharedFolders/FeatureSharedFolders.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Features/SharedFolders/FeatureSharedFolders.cs
@@ -148,8 +148,7 @@ namespace Acacia.Features.SharedFolders
 
         public void Sync(ZPushAccount account)
         {
-            Watcher.Sync.Resync();
-            account.Account.SendReceive();
+            account.Account.SendReceive(new AcaciaTask(null, this, "SyncShares", () => SyncShares(account)));
         }
 
         private void SyncShares(ZPushAccount account)
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAccount.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAccount.cs
index 3240b00..0887310 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAccount.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAccount.cs
@@ -1,6 +1,4 @@
-
-using Acacia.Native.MAPI;
-/// Copyright 2017 Kopano b.v.
+/// Copyright 2018 Kopano b.v.
 /// 
 /// This program is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License, version 3,
@@ -21,6 +19,8 @@ using System.Linq;
 using System.Security;
 using System.Text;
 using System.Threading.Tasks;
+using Acacia.Native.MAPI;
+using Acacia.Utils;
 
 namespace Acacia.Stubs
 {
@@ -32,7 +32,7 @@ namespace Acacia.Stubs
 
         IStore Store { get; }
 
-        void SendReceive();
+        void SendReceive(AcaciaTask after = null);
 
         string DisplayName { get; }
 
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAddIn.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAddIn.cs
index 960c338..90dd36f 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAddIn.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/IAddIn.cs
@@ -1,4 +1,4 @@
-/// Copyright 2017 Kopano b.v.
+/// Copyright 2018 Kopano b.v.
 /// 
 /// This program is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License, version 3,
@@ -62,7 +62,7 @@ namespace Acacia.Stubs
         /// <summary>
         /// Sends and receives all accounts, or a specific account.
         /// </summary>
-        void SendReceive(IAccount account = null);
+        void SendReceive(IAccount account = null, AcaciaTask after = null);
 
         /// <summary>
         /// Restarts the application
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AccountWrapper.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AccountWrapper.cs
index 847932d..a7087e0 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AccountWrapper.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AccountWrapper.cs
@@ -72,9 +72,9 @@ namespace Acacia.Stubs.OutlookWrappers
         /// <summary>
         /// Triggers an Outlook send/receive operation for this account.
         /// </summary>
-        public void SendReceive()
+        public void SendReceive(AcaciaTask after = null)
         {
-            ThisAddIn.Instance.SendReceive(this);
+            ThisAddIn.Instance.SendReceive(this, after);
         }
 
         #region Properties
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AddInWrapper.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AddInWrapper.cs
index 34e9c41..0e52811 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AddInWrapper.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/Stubs/OutlookWrappers/AddInWrapper.cs
@@ -137,8 +137,13 @@ namespace Acacia.Stubs.OutlookWrappers
             }
         }
 
-        public void SendReceive(IAccount account)
+        public void SendReceive(IAccount account, AcaciaTask after)
         {
+            if (after != null)
+            {
+                Watcher.Sync.AddEndTaskOnce(after);
+            }
+
             // TODO: send/receive specific account
             NSOutlook.NameSpace session = _app.Session;
             try
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushSync.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushSync.cs
index 0d5ce13..759f3e9 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushSync.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushSync.cs
@@ -1,4 +1,4 @@
-/// Copyright 2017 Kopano b.v.
+/// Copyright 2018 Kopano b.v.
 /// 
 /// This program is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License, version 3,
@@ -19,6 +19,7 @@ using Acacia.Stubs;
 using Acacia.Utils;
 using Acacia.ZPush.Connect;
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -223,6 +224,11 @@ namespace Acacia.ZPush
             }
         }
 
+        public void AddEndTaskOnce(AcaciaTask after)
+        {
+            _endTasks.Enqueue(after);
+        }
+
         #endregion
 
         #region Setup 
@@ -261,6 +267,7 @@ namespace Acacia.ZPush
                 // Need to keep a reference to keep receiving events
                 _syncObject = addIn.GetSyncObject();
                 _syncObject.SyncStart += SyncObject_SyncStart;
+                _syncObject.SyncEnd += SyncObject_SyncEnd;
                 watcher.AccountDiscovered += Watcher_AccountDiscovered;
             }
         }
@@ -282,11 +289,6 @@ namespace Acacia.ZPush
             _started = true;
         }
 
-        public void Resync()
-        {
-            LastSyncTime = new DateTime();
-        }
-
         /// <summary>
         /// Delegate for an account-specific task.
         /// </summary>
@@ -499,6 +501,20 @@ namespace Acacia.ZPush
             }
         }
 
+        private readonly ConcurrentQueue<AcaciaTask> _endTasks = new ConcurrentQueue<AcaciaTask>();
+
+        /// <summary>
+        /// Invoked after an explicit send and receive is performed, invokes any tasks.
+        /// </summary>
+        private void SyncObject_SyncEnd()
+        {
+            AcaciaTask task;
+            while (_endTasks.TryDequeue(out task))
+            {
+                Tasks.Task(task, false);
+            }
+        }
+
         #endregion
     }
 }
diff --git a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushTypes.cs b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushTypes.cs
index 94656e6..b81e512 100644
--- a/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushTypes.cs
+++ b/src/AcaciaZPushPlugin/AcaciaZPushPlugin/ZPush/ZPushTypes.cs
@@ -63,6 +63,8 @@ namespace Acacia.ZPush
 
         public override bool Equals(object obj)
         {
+            if (obj == null)
+                return false;
             return (this.GetType() == obj.GetType()) && ((ZPushId)obj)._id.ToLower().Equals(_id.ToLower());
         }