diff --git a/src/Orchard/Environment/DefaultOrchardHost.cs b/src/Orchard/Environment/DefaultOrchardHost.cs
index b8aff35e6..defd71ed7 100644
--- a/src/Orchard/Environment/DefaultOrchardHost.cs
+++ b/src/Orchard/Environment/DefaultOrchardHost.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Linq;
 using System.Collections.Generic;
-
 using Orchard.Caching;
 using Orchard.Environment.Configuration;
 using Orchard.Environment.Extensions;
@@ -26,7 +25,9 @@ namespace Orchard.Environment {
         private readonly static object _syncLock = new object();
 
         private IEnumerable<ShellContext> _shellContexts;
-        private IEnumerable<ShellSettings> _tenantsToRestart; 
+        
+        [ThreadStatic]
+        private static IList<ShellSettings> _tenantsToRestart;
 
         public DefaultOrchardHost(
             IShellSettingsManager shellSettingsManager,
@@ -45,7 +46,6 @@ namespace Orchard.Environment {
             _extensionMonitoringCoordinator = extensionMonitoringCoordinator;
             _cacheManager = cacheManager;
             _hostLocalRestart = hostLocalRestart;
-            _tenantsToRestart = Enumerable.Empty<ShellSettings>();
 
             T = NullLocalizer.Instance;
             Logger = NullLogger.Instance;
@@ -109,13 +109,12 @@ namespace Orchard.Environment {
         }
 
         void StartUpdatedShells() {
-            lock (_syncLock) {
-                if (_tenantsToRestart.Any()) {
-                    foreach (var settings in _tenantsToRestart.ToList()) {
-                        ActivateShell(settings);
-                    }
-
-                    _tenantsToRestart = Enumerable.Empty<ShellSettings>();
+            while (_tenantsToRestart != null && _tenantsToRestart.Any()) {
+                var settings = _tenantsToRestart.First();
+                _tenantsToRestart.Remove(settings);
+                Logger.Debug("Updating shell: " + settings.Name);
+                lock (_syncLock) {
+                    ActivateShell(settings);
                 }
             }
         }
@@ -148,7 +147,7 @@ namespace Orchard.Environment {
         }
 
         /// <summary>
-        /// Start a Shell and register its settings in RunningShellTable
+        /// Starts a Shell and registers its settings in RunningShellTable
         /// </summary>
         private void ActivateShell(ShellContext context) {
             Logger.Debug("Activating context for tenant {0}", context.Settings.Name); 
@@ -161,13 +160,19 @@ namespace Orchard.Environment {
             
             _runningShellTable.Add(context.Settings);
         }
-
-        ShellContext CreateSetupContext() {
+        
+        /// <summary>
+        /// Creates a transient shell for the default tenant's setup
+        /// </summary>
+        private ShellContext CreateSetupContext() {
             Logger.Debug("Creating shell context for root setup");
             return _shellContextFactory.CreateSetupContext(new ShellSettings { Name = ShellSettings.DefaultName });
         }
 
-        ShellContext CreateShellContext(ShellSettings settings) {
+        /// <summary>
+        /// Creates a shell context based on shell settings
+        /// </summary>
+        private ShellContext CreateShellContext(ShellSettings settings) {
             if (settings.State == TenantState.Uninitialized) {
                 Logger.Debug("Creating shell context for tenant {0} setup", settings.Name);
                 return _shellContextFactory.CreateSetupContext(settings);
@@ -227,26 +232,30 @@ namespace Orchard.Environment {
             // of the pipeline, as the request transaction has been closed, so creating a new
             // environment and transaction for these tasks will behave as expected.)
             while (_processingEngine.AreTasksPending()) {
+                Logger.Debug("Processing pending task");
                 _processingEngine.ExecuteNextTask();
             }
+
+            StartUpdatedShells();
         }
 
-        /// <summary>
-        /// Register and activate a new Shell when a tenant is created
-        /// </summary>
         void IShellSettingsManagerEventHandler.Saved(ShellSettings settings) {
-            lock (_syncLock) {
+            Logger.Debug("Shell saved: " + settings.Name);
+
+            // if a tenant has been created
+            if (settings.State != TenantState.Invalid) {
+                _tenantsToRestart = _tenantsToRestart ?? new List<ShellSettings>();
                 
-                // if a tenant has been altered, and is not invalid, reload it
-                if (settings.State != TenantState.Invalid) {
-                    _tenantsToRestart = _tenantsToRestart
-                        .Where(x => x.Name != settings.Name)
-                        .Concat(new[] { settings });
+                if (!_tenantsToRestart.Any(t => t.Name.Equals(settings.Name))) {
+                    Logger.Debug("Adding tenant to restart: " + settings.Name + " " + settings.State);
+                    _tenantsToRestart.Add(settings);
                 }
             }
         }
 
-        void ActivateShell(ShellSettings settings) {
+        public void ActivateShell(ShellSettings settings) {
+            Logger.Debug("Activating shell: " + settings.Name);
+
             // look for the associated shell context
             var shellContext = _shellContexts.FirstOrDefault(c => c.Settings.Name == settings.Name);
 
@@ -276,32 +285,28 @@ namespace Orchard.Environment {
         }
 
         /// <summary>
-        /// A feature is enabled/disabled
+        /// A feature is enabled/disabled, the tenant needs to be restarted
         /// </summary>
         void IShellDescriptorManagerEventHandler.Changed(ShellDescriptor descriptor, string tenant) {
-            lock (_syncLock) {
-                
-                if (_shellContexts == null) {
-                    return;
-                }
-
-                var context =_shellContexts.FirstOrDefault(x => x.Settings.Name == tenant);
-                
-                // some shells might need to be started, e.g. created by command line
-                if(context == null) {
-                    StartUpdatedShells();
-                    context = _shellContexts.First(x => x.Settings.Name == tenant);
-                }
-
-                // don't flag the tenant if already listed
-                if(_tenantsToRestart.Any(x => x.Name == tenant)) {
-                    return;
-                }
-
-                _tenantsToRestart = _tenantsToRestart
-                    .Concat(new[] { context.Settings })
-                    .ToArray();
+            if (_shellContexts == null) {
+                return;
             }
+            
+            Logger.Debug("Shell changed: " + tenant);
+
+            var context = _shellContexts.FirstOrDefault(x => x.Settings.Name == tenant);
+
+            if (context == null) {
+                return;
+            }
+
+            // don't flag the tenant if already listed
+            if (_tenantsToRestart.Any(x => x.Name == tenant)) {
+                return;
+            }
+
+            Logger.Debug("Adding tenant to restart: " + tenant);
+            _tenantsToRestart.Add(context.Settings);
         }
     }
 }
diff --git a/src/Orchard/Environment/IHostLocalRestart.cs b/src/Orchard/Environment/IHostLocalRestart.cs
index b19bb4eb0..90a2371d2 100644
--- a/src/Orchard/Environment/IHostLocalRestart.cs
+++ b/src/Orchard/Environment/IHostLocalRestart.cs
@@ -34,11 +34,11 @@ namespace Orchard.Environment {
         }
 
         void IShellSettingsManagerEventHandler.Saved(ShellSettings settings) {
-            TouchFile();
+            //TouchFile();
         }
 
         void IShellDescriptorManagerEventHandler.Changed(ShellDescriptor descriptor, string tenant) {
-            TouchFile();
+            //TouchFile();
         }
 
         private void TouchFile() {