diff --git a/Source/TeamMate/Services/ResolverService.cs b/Source/TeamMate/Services/ResolverService.cs
index 7de0138..29ab166 100644
--- a/Source/TeamMate/Services/ResolverService.cs
+++ b/Source/TeamMate/Services/ResolverService.cs
@@ -1,4 +1,5 @@
 using Microsoft.VisualStudio.Services.Graph.Client;
+using Microsoft.VisualStudio.Services.Users;
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
@@ -10,13 +11,15 @@ namespace Microsoft.Tools.TeamMate.Services
 {
     public class ResolverService
     {
-        private List<GraphUser> GraphUserCache { get; set; }
+        private Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor> GraphUserCache { get; set; }
 
-        private List<GraphGroup> GraphGroupCache { get; set; }
+        private Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor> GraphGroupCache { get; set; }
         
         private List<Task> Tasks = new List<Task>();
 
-        private async Task<List<GraphUser>> FetchUsersAsync(
+        private bool Cached = false;
+
+        private async Task<Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor>> FetchUsersAsync(
             GraphHttpClient graphClient)
         {
             if (GraphUserCache != null)
@@ -24,7 +27,7 @@ private async Task<List<GraphUser>> FetchUsersAsync(
                 return GraphUserCache;
             }
 
-            List<GraphUser> users = new List<GraphUser>();
+            var users = new Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor>();
 
             string continuationToken = null;
             do
@@ -33,7 +36,10 @@ private async Task<List<GraphUser>> FetchUsersAsync(
                 continuationToken = data.ContinuationToken != null ? data.ContinuationToken.First() : null;
                 foreach (var user in data.GraphUsers)
                 {
-                    users.Add(user);
+                    if (user.MailAddress != null)
+                    {
+                        users[user.MailAddress] = user.Descriptor;
+                    }
                 }
             }
             while (continuationToken != null);
@@ -43,7 +49,7 @@ private async Task<List<GraphUser>> FetchUsersAsync(
             return users;
         }
 
-        private async Task<List<GraphGroup>> FetchGroupsAsync(
+        private async Task<Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor>> FetchGroupsAsync(
             GraphHttpClient graphClient)
         {
             if (GraphGroupCache != null)
@@ -51,7 +57,7 @@ private async Task<List<GraphGroup>> FetchGroupsAsync(
                 return GraphGroupCache;
             }
 
-            List<GraphGroup> groups = new List<GraphGroup>();
+            var groups = new Dictionary<string, VisualStudio.Services.Common.SubjectDescriptor>();
 
             string continuationToken = null;
             do
@@ -61,7 +67,10 @@ private async Task<List<GraphGroup>> FetchGroupsAsync(
                 continuationToken = data.ContinuationToken != null ? data.ContinuationToken.First() : null;
                 foreach (var group in data.GraphGroups)
                 {
-                    groups.Add(group);
+                    if (group.MailAddress != null)
+                    {
+                        groups[group.MailAddress] = group.Descriptor;
+                    }
                 }
             }
             while (continuationToken != null);
@@ -71,11 +80,19 @@ private async Task<List<GraphGroup>> FetchGroupsAsync(
             return groups;
         }
 
-        public void FetchDataSync(
+        private void FetchDataSyncIfNeeded(
             GraphHttpClient client)
         {
-            Tasks.Add(FetchUsersAsync(client));
-            Tasks.Add(FetchGroupsAsync(client));
+            lock (Tasks)
+            {
+                if (!Cached)
+                {
+                    Tasks.Add(FetchUsersAsync(client));
+                    Tasks.Add(FetchGroupsAsync(client));
+
+                    Cached = true;
+                }
+            }
         }
 
         public async Task<Guid?> Resolve(
@@ -87,14 +104,15 @@ public void FetchDataSync(
                 return null;
             }
 
+            this.FetchDataSyncIfNeeded(client);
+
             await Task.Run(() => { foreach (var task in this.Tasks) { task.Wait(); } });
 
             foreach (var user in GraphUserCache)
             {
-                if (user.MailAddress != null &&
-                    (user.MailAddress.Contains(value)))
+                if (user.Key.Contains(value))
                 {
-                    var storageKey = client.GetStorageKeyAsync(user.Descriptor).Result;
+                    var storageKey = client.GetStorageKeyAsync(user.Value).Result;
 
                     return storageKey.Value;
                 }
@@ -102,17 +120,15 @@ public void FetchDataSync(
 
             foreach (var group in GraphGroupCache)
             {
-                if (group.MailAddress != null &&
-                    (group.MailAddress.Contains(value)))
+                if (group.Key.Contains(value))
                 {
-                    var storageKey = client.GetStorageKeyAsync(group.Descriptor).Result;
+                    var storageKey = client.GetStorageKeyAsync(group.Value).Result;
 
                     return storageKey.Value;
                 }
             }
 
             throw new ArgumentException("Could not resolve '" + value + "'. Try the full email for the person and/or group.");
-
         }
     }
 }
diff --git a/Source/TeamMate/Services/VstsConnectionService.cs b/Source/TeamMate/Services/VstsConnectionService.cs
index cd90b7c..1bf7a97 100644
--- a/Source/TeamMate/Services/VstsConnectionService.cs
+++ b/Source/TeamMate/Services/VstsConnectionService.cs
@@ -190,9 +190,6 @@ private async Task<ProjectContext> DoConnectAsync(ProjectInfo projectInfo, Cance
                 projectContext.WorkItemFieldsByName = fields.ToDictionary(f => f.ReferenceName, StringComparer.OrdinalIgnoreCase);
                 projectContext.RequiredWorkItemFieldNames = GetWorkItemFieldsToPrefetch(projectContext.WorkItemFieldsByName);
 
-                this.ResolverService.FetchDataSync(
-                   graphClient);
-
                 return projectContext;
             }
             catch (Exception e)