diff --git a/OpenSim/Framework/Monitoring/JobEngine.cs b/OpenSim/Framework/Monitoring/JobEngine.cs
index 7f15243521..79cd563874 100644
--- a/OpenSim/Framework/Monitoring/JobEngine.cs
+++ b/OpenSim/Framework/Monitoring/JobEngine.cs
@@ -137,7 +137,7 @@ namespace OpenSim.Framework.Monitoring
                     }
                     if (m_jobQueue != null)
                     {
-                        m_jobQueue .Dispose();
+                        m_jobQueue.Dispose();
                         m_jobQueue = null;
                     }
                 }
diff --git a/OpenSim/Framework/ViewerSky.cs b/OpenSim/Framework/ViewerSky.cs
index d87dacf42d..4d850cea3c 100644
--- a/OpenSim/Framework/ViewerSky.cs
+++ b/OpenSim/Framework/ViewerSky.cs
@@ -147,7 +147,7 @@ namespace OpenSim.Framework
 
         //this is a vector3 now, but all viewers expect a vector4, so keeping like this for now
         public Vector4 sunlight_color = new Vector4(0.7342f, 0.7815f, 0.9f, 0.3f);
-        public string Name = "Default";
+        public string Name = "DefaultSky";
 
         public float cloud_variance = 0;
         public float dome_offset = 0.96f;
diff --git a/OpenSim/Framework/WebUtil.cs b/OpenSim/Framework/WebUtil.cs
index d2338a35ff..1d95fd1d8d 100644
--- a/OpenSim/Framework/WebUtil.cs
+++ b/OpenSim/Framework/WebUtil.cs
@@ -53,9 +53,7 @@ namespace OpenSim.Framework
     /// </summary>
     public static class WebUtil
     {
-        private static readonly ILog m_log =
-                LogManager.GetLogger(
-                MethodBase.GetCurrentMethod().DeclaringType);
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         /// <summary>
         /// Control the printing of certain debug messages.
diff --git a/OpenSim/Region/ClientStack/Linden/Caps/GetAssetsModule.cs b/OpenSim/Region/ClientStack/Linden/Caps/GetAssetsModule.cs
index dcf9cd4eef..4b60a93d71 100755
--- a/OpenSim/Region/ClientStack/Linden/Caps/GetAssetsModule.cs
+++ b/OpenSim/Region/ClientStack/Linden/Caps/GetAssetsModule.cs
@@ -232,7 +232,6 @@ namespace OpenSim.Region.ClientStack.Linden
             private HashSet<UUID> dropedResponses = new HashSet<UUID>();
 
             private Scene m_scene;
-            private ScenePresence m_presence;
             public PollServiceAssetEventArgs(string uri, UUID pId, Scene scene) :
                 base(null, uri, null, null, null, null, pId, int.MaxValue)
             {
@@ -245,20 +244,19 @@ namespace OpenSim.Region.ClientStack.Linden
                         APollResponse response;
                         if (responses.TryGetValue(requestID, out response))
                         {
-                            if (m_presence == null)
-                                m_presence = m_scene.GetScenePresence(pId);
+                            ScenePresence sp = m_scene.GetScenePresence(pId);
 
-                            if (m_presence == null || m_presence.IsDeleted)
+                            if (sp == null || sp.IsDeleted)
                                 return true;
 
                             OSHttpResponse resp = response.osresponse;
 
                             if(Util.GetTimeStamp() - resp.RequestTS > (resp.RawBufferLen > 2000000 ? 200 : 90))
-                                return m_presence.CapCanSendAsset(2, resp.RawBufferLen);
+                                return sp.CapCanSendAsset(2, resp.RawBufferLen);
 
                             if (resp.Priority > 1)
-                                return m_presence.CapCanSendAsset(1, resp.RawBufferLen);
-                            return m_presence.CapCanSendAsset(2, resp.RawBufferLen);
+                                return sp.CapCanSendAsset(1, resp.RawBufferLen);
+                            return sp.CapCanSendAsset(2, resp.RawBufferLen);
                         }
                         return false;
                     }
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
index 21e61a73b2..afdcf4786c 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
@@ -748,9 +748,10 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 m_nextOnQueueEmpty = start + MIN_CALLBACK_MS;
 
                 // Asynchronously run the callback
-                if (m_udpServer.OqrEngine.IsRunning)
-                    m_udpServer.OqrEngine.QueueJob(AgentID.ToString(), () => FireQueueEmpty(categories));
-                else
+                // avoid stupid memory leak
+                //if (m_udpServer.OqrEngine.IsRunning)
+                //    m_udpServer.OqrEngine.QueueJob(AgentID.ToString(), () => FireQueueEmpty(categories));
+                //else
                     Util.FireAndForget(FireQueueEmpty, categories, "LLUDPClient.BeginFireQueueEmpty");
             }
         }
@@ -764,16 +765,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// signature</param>
         public void FireQueueEmpty(object o)
         {
-            ThrottleOutPacketTypeFlags categories = (ThrottleOutPacketTypeFlags)o;
             QueueEmpty callback = OnQueueEmpty;
-
             if (callback != null)
             {
-                // if (m_udpServer.IsRunningOutbound)
-                // {
+                ThrottleOutPacketTypeFlags categories = (ThrottleOutPacketTypeFlags)o;
                 try { callback(categories); }
                 catch (Exception e) { m_log.Error("[LLUDPCLIENT]: OnQueueEmpty(" + categories + ") threw an exception: " + e.Message, e); }
-                // }
             }
 
             m_isQueueEmptyRunning = false;
diff --git a/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs b/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
index 02c73bdfc1..5b2d15aa36 100755
--- a/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
+++ b/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
@@ -28,9 +28,8 @@
 using System;
 using System.IO;
 using System.Collections.Generic;
-using System.Linq;
+using System.Collections.Concurrent;
 using System.Reflection;
-using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.Text;
 using System.Threading;
@@ -40,7 +39,6 @@ using Nini.Config;
 using Mono.Addins;
 using OpenMetaverse;
 using OpenSim.Framework;
-using OpenSim.Framework.Console;
 using OpenSim.Framework.Monitoring;
 using OpenSim.Region.Framework.Interfaces;
 using OpenSim.Region.Framework.Scenes;
@@ -53,6 +51,12 @@ namespace OpenSim.Region.CoreModules.Asset
     [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "FlotsamAssetCache")]
     public class FlotsamAssetCache : ISharedRegionModule, IAssetCache, IAssetService
     {
+        private struct WriteAssetInfo
+        {
+            public string filename;
+            public AssetBase asset;
+        }
+
         private static readonly ILog m_log = LogManager.GetLogger( MethodBase.GetCurrentMethod().DeclaringType);
 
         private bool m_Enabled;
@@ -76,6 +80,8 @@ namespace OpenSim.Region.CoreModules.Asset
         private ulong m_weakRefHits;
 
         private static HashSet<string> m_CurrentlyWriting = new HashSet<string>();
+        private static BlockingCollection<WriteAssetInfo> m_assetFileWriteQueue = null;
+        private static CancellationTokenSource m_cancelSource;
 
         private bool m_FileCacheEnabled = true;
 
@@ -116,8 +122,6 @@ namespace OpenSim.Region.CoreModules.Asset
             m_InvalidChars = invalidChars.ToArray();
         }
 
-        private static JobEngine m_DiskWriterEngine = null;
-
         public Type ReplaceableInterface
         {
             get { return null; }
@@ -219,6 +223,19 @@ namespace OpenSim.Region.CoreModules.Asset
 
         public void Close()
         {
+            if(m_Scenes.Count <= 0)
+            {
+                if (m_assetFileWriteQueue != null)
+                {
+                    m_assetFileWriteQueue.Dispose();
+                    m_assetFileWriteQueue = null;
+                }
+                if(m_cancelSource != null)
+                {
+                    m_cancelSource.Dispose();
+                    m_cancelSource = null;
+                }
+            }
         }
 
         public void AddRegion(Scene scene)
@@ -238,13 +255,16 @@ namespace OpenSim.Region.CoreModules.Asset
                 m_Scenes.Remove(scene);
                 lock(timerLock)
                 {
-                    if(m_timerRunning && m_Scenes.Count <= 0)
+                    if(m_Scenes.Count <= 0)
                     {
-                        m_timerRunning = false;
-                        m_CacheCleanTimer.Stop();
-                        m_CacheCleanTimer.Close();
-                        if (m_FileCacheEnabled && m_DiskWriterEngine != null && m_DiskWriterEngine.IsRunning)
-                            m_DiskWriterEngine.Stop();
+                        if (m_timerRunning)
+                        {
+                            m_timerRunning = false;
+                            m_CacheCleanTimer.Stop();
+                            m_CacheCleanTimer.Close();
+                        }
+                        if (m_FileCacheEnabled && m_assetFileWriteQueue != null)
+                            m_cancelSource.Cancel();
                     }
                 }
             }
@@ -270,15 +290,31 @@ namespace OpenSim.Region.CoreModules.Asset
                         }
                     }
 
-                    if(m_DiskWriterEngine == null)
+                    if (m_FileCacheEnabled && m_assetFileWriteQueue == null)
                     {
-                        m_DiskWriterEngine = new JobEngine("FlotsamWriter", "FlotsamWriter");
-                        m_DiskWriterEngine.Start();
+                        m_assetFileWriteQueue = new BlockingCollection<WriteAssetInfo>();
+                        m_cancelSource = new CancellationTokenSource();
+                        WorkManager.RunInThreadPool(processWrites, null, "FloatsamCacheWriter", false);
                     }
                 }
             }
         }
 
+        private void processWrites(object o)
+        {
+            try
+            {
+                while(true)
+                {
+                    if(m_assetFileWriteQueue.TryTake(out WriteAssetInfo wai,-1, m_cancelSource.Token))
+                    {
+                        WriteFileCache(wai.filename,wai.asset,false);
+                    }
+                }
+            }
+            catch{ }
+        }
+
         ////////////////////////////////////////////////////////////
         // IAssetCache
         //
@@ -302,6 +338,9 @@ namespace OpenSim.Region.CoreModules.Asset
 
         private void UpdateFileCache(string key, AssetBase asset, bool replace = false)
         {
+            if(m_assetFileWriteQueue == null)
+                return;
+
             string filename = GetFileName(key);
 
             try
@@ -323,8 +362,11 @@ namespace OpenSim.Region.CoreModules.Asset
                         m_CurrentlyWriting.Add(filename);
                 }
 
-                // weakreferences should hold and return the asset while async write happens
-                m_DiskWriterEngine?.QueueJob("", delegate { WriteFileCache(filename, asset, replace); });
+                WriteAssetInfo wai = new WriteAssetInfo();
+                wai.filename = filename;
+                wai.asset = asset;
+                if (m_assetFileWriteQueue != null)
+                    m_assetFileWriteQueue.Add(wai);
             }
             catch (Exception e)
             {
diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index 8e1b6f6985..34c552e66f 100755
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -1664,20 +1664,24 @@ namespace OpenSim.Region.Framework.Scenes
 */
                     if (Frame % (m_update_coarse_locations) == 0 && !m_sendingCoarseLocations)
                     {
-                        m_sendingCoarseLocations = true;
-                        WorkManager.RunInThreadPool(
-                            delegate
-                            {
-                                List<Vector3> coarseLocations;
-                                List<UUID> avatarUUIDs;
-                                SceneGraph.GetCoarseLocations(out coarseLocations, out avatarUUIDs, 60);
-                                // Send coarse locations to clients
-                                ForEachScenePresence(delegate(ScenePresence presence)
+                        if(GetNumberOfClients() > 0)
+                        {
+                            m_sendingCoarseLocations = true;
+                            WorkManager.RunInThreadPool(
+                                delegate
                                 {
-                                    presence.SendCoarseLocations(coarseLocations, avatarUUIDs);
-                                });
-                                m_sendingCoarseLocations = false; 
-                            }, null, string.Format("SendCoarseLocations ({0})", Name));
+                                    List<Vector3> coarseLocations;
+                                    List<UUID> avatarUUIDs;
+                                    SceneGraph.GetCoarseLocations(out coarseLocations, out avatarUUIDs, 60);
+                                    // Send coarse locations to clients
+                                    ForEachScenePresence(delegate(ScenePresence presence)
+                                    {
+                                        if(!presence.IsNPC)
+                                            presence.SendCoarseLocations(coarseLocations, avatarUUIDs);
+                                    });
+                                    m_sendingCoarseLocations = false; 
+                                }, null, string.Format("SendCoarseLocations ({0})", Name));
+                        }
                     }
 
                     // Get the simulation frame time that the avatar force input
diff --git a/OpenSim/Server/Base/ServerUtils.cs b/OpenSim/Server/Base/ServerUtils.cs
index 5fc3d72bd6..9a374d19e6 100644
--- a/OpenSim/Server/Base/ServerUtils.cs
+++ b/OpenSim/Server/Base/ServerUtils.cs
@@ -564,6 +564,29 @@ namespace OpenSim.Server.Base
             return new Dictionary<string, object>();
         }
 
+        public static Dictionary<string, object> ParseXmlResponse(Stream src)
+        {
+            //m_log.DebugFormat("[XXX]: received xml string: {0}", data);
+
+            try
+            {
+                XmlReaderSettings xset = new XmlReaderSettings() { IgnoreWhitespace = true, IgnoreComments = true, ConformanceLevel = ConformanceLevel.Fragment, CloseInput = true };
+                XmlParserContext xpc = new XmlParserContext(null, null, null, XmlSpace.None);
+                xpc.Encoding = Util.UTF8NoBomEncoding;
+                using (XmlReader xr = XmlReader.Create(src, xset, xpc))
+                {
+                    if (!xr.ReadToFollowing("ServerResponse"))
+                        return new Dictionary<string, object>();
+                    return ScanXmlResponse(xr);
+                }
+            }
+            catch (Exception e)
+            {
+                m_log.DebugFormat("[serverUtils.ParseXmlResponse]: failed error: {0}", e.Message);
+            }
+            return new Dictionary<string, object>();
+        }
+
         public static IConfig GetConfig(string configFile, string configName)
         {
             IConfig config;
diff --git a/bin/OpenSimDefaults.ini b/bin/OpenSimDefaults.ini
index 9ec83a1ad4..a3df908663 100644
--- a/bin/OpenSimDefaults.ini
+++ b/bin/OpenSimDefaults.ini
@@ -770,7 +770,7 @@
     Cap_DispatchRegionInfo = ""
     Cap_EstateAccess = "localhost"
     //Cap_EstateChangeInfo = "localhost"  broken on viewers
-    Cap_EnvironmentSettings = "localhost"
+    Cap_EnvironmentSettings = "localhost" // this also controls ExtEnviroment cap
     Cap_EventQueueGet = "localhost"
     Cap_FetchInventory = ""
     Cap_ObjectMedia = "localhost"