diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/LocalUserAccountServiceConnector.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/LocalUserAccountServiceConnector.cs
index 3127199586..a413a8bff1 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/LocalUserAccountServiceConnector.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/LocalUserAccountServiceConnector.cs
@@ -154,14 +154,12 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         {
             bool inCache = false;
             UserAccount account;
-            lock(m_Cache)
-               account = m_Cache.Get(userID, out inCache);
+            account = m_Cache.Get(userID, out inCache);
             if (inCache)
                 return account;
 
             account = UserAccountService.GetUserAccount(scopeID, userID);
-            lock(m_Cache)
-                m_Cache.Cache(userID, account);
+            m_Cache.Cache(userID, account);
 
             return account;
         }
@@ -170,15 +168,13 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         {
             bool inCache = false;
             UserAccount account;
-            lock(m_Cache)
-                account = m_Cache.Get(firstName + " " + lastName, out inCache);
+            account = m_Cache.Get(firstName + " " + lastName, out inCache);
             if (inCache)
                 return account;
 
             account = UserAccountService.GetUserAccount(scopeID, firstName, lastName);
             if (account != null)
-                lock(m_Cache)
-                    m_Cache.Cache(account.PrincipalID, account);
+                m_Cache.Cache(account.PrincipalID, account);
 
             return account;
         }
@@ -201,8 +197,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
             {
                 if(UUID.TryParse(id, out uuid))
                 {
-                    lock(m_Cache)
-                        account = m_Cache.Get(uuid, out inCache);
+                    account = m_Cache.Get(uuid, out inCache);
                     if (inCache)
                         ret.Add(account);
                     else                        
@@ -220,8 +215,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
                 foreach(UserAccount acc in ext)
                 {
                     if(acc != null)
-                        lock(m_Cache)
-                            m_Cache.Cache(acc.PrincipalID, acc);
+                        m_Cache.Cache(acc.PrincipalID, acc);
                 }
             }
             return ret;
diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/RemoteUserAccountServiceConnector.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/RemoteUserAccountServiceConnector.cs
index 9140d786f5..60dd97ad90 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/RemoteUserAccountServiceConnector.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/RemoteUserAccountServiceConnector.cs
@@ -128,8 +128,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         // flags, title, etc. And country, don't forget country!
         private void OnNewClient(IClientAPI client)
         {
-            lock(m_Cache)
-                m_Cache.Remove(client.Name);
+            m_Cache.Remove(client.Name);
         }
 
         #region Overwritten methods from IUserAccountService
@@ -138,17 +137,14 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         {
             bool inCache = false;
             UserAccount account;
-            lock(m_Cache)
-                account = m_Cache.Get(userID, out inCache);
+            account = m_Cache.Get(userID, out inCache);
             if (inCache)
                 return account;
 
             account = base.GetUserAccount(scopeID, userID);
             if(account != null)
-            {
-                lock(m_Cache)
-                    m_Cache.Cache(userID, account);
-            }
+                m_Cache.Cache(userID, account);
+
             return account;
         }
 
@@ -156,17 +152,14 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         {
             bool inCache = false;
             UserAccount account;
-            lock(m_Cache)
-                account = m_Cache.Get(firstName + " " + lastName, out inCache);
+            account = m_Cache.Get(firstName + " " + lastName, out inCache);
             if (inCache)
                 return account;
 
             account = base.GetUserAccount(scopeID, firstName, lastName);
             if (account != null)
-            {
-                lock(m_Cache)
-                    m_Cache.Cache(account.PrincipalID, account);
-            }
+                m_Cache.Cache(account.PrincipalID, account);
+
             return account;
         }
 
@@ -183,8 +176,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
             {
                 if(UUID.TryParse(id, out uuid))
                 {
-                    lock(m_Cache)
-                        account = m_Cache.Get(uuid, out inCache);
+                    account = m_Cache.Get(uuid, out inCache);
                     if (inCache)
                         accs.Add(account);
                     else
@@ -202,8 +194,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
                         if(acc != null)
                         {
                             accs.Add(acc);
-                            lock(m_Cache)
-                                m_Cache.Cache(acc.PrincipalID, acc);
+                            m_Cache.Cache(acc.PrincipalID, acc);
                         }
                     }
                 }
diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/UserAccountCache.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/UserAccountCache.cs
index 53610d95af..97baf8703a 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/UserAccountCache.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/UserAccounts/UserAccountCache.cs
@@ -44,6 +44,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         
         private ExpiringCache<UUID, UserAccount> m_UUIDCache;
         private ExpiringCache<string, UUID> m_NameCache;
+        private object accessLock = new object();
 
         public UserAccountCache()
         {
@@ -54,60 +55,73 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
         public void Cache(UUID userID, UserAccount account)
         {
             // Cache even null accounts
-            m_UUIDCache.AddOrUpdate(userID, account, CACHE_EXPIRATION_SECONDS);
-            if (account != null)
-                m_NameCache.AddOrUpdate(account.Name, account.PrincipalID, CACHE_EXPIRATION_SECONDS);
+            lock(accessLock)
+            {
+                m_UUIDCache.AddOrUpdate(userID, account, CACHE_EXPIRATION_SECONDS);
+                if (account != null)
+                    m_NameCache.AddOrUpdate(account.Name, account.PrincipalID, CACHE_EXPIRATION_SECONDS);
 
             //m_log.DebugFormat("[USER CACHE]: cached user {0}", userID);
+            }
         }
 
         public void Invalidate(UUID userID)
         {
-            m_UUIDCache.Remove(userID);
+            lock(accessLock)
+                m_UUIDCache.Remove(userID);
         }
 
         public UserAccount Get(UUID userID, out bool inCache)
         {
             UserAccount account = null;
             inCache = false;
-            if (m_UUIDCache.TryGetValue(userID, out account))
+            lock(accessLock)
             {
-                //m_log.DebugFormat("[USER CACHE]: Account {0} {1} found in cache", account.FirstName, account.LastName);
-                inCache = true;
-                return account;
+                if (m_UUIDCache.TryGetValue(userID, out account))
+                {
+                    //m_log.DebugFormat("[USER CACHE]: Account {0} {1} found in cache", account.FirstName, account.LastName);
+                    inCache = true;
+                    return account;
+                }
             }
-
             return null;
         }
 
         public UserAccount Get(string name, out bool inCache)
         {
             inCache = false;
-            if (!m_NameCache.Contains(name))
-                return null;
+            lock(accessLock)
+            {
+                if (!m_NameCache.Contains(name))
+                    return null;
 
-            UserAccount account = null;
-            UUID uuid = UUID.Zero;
-            if (m_NameCache.TryGetValue(name, out uuid))
-                if (m_UUIDCache.TryGetValue(uuid, out account))
+                UserAccount account = null;
+                UUID uuid = UUID.Zero;
+                if (m_NameCache.TryGetValue(name, out uuid))
                 {
-                    inCache = true;
-                    return account;
+                    if (m_UUIDCache.TryGetValue(uuid, out account))
+                    {
+                        inCache = true;
+                        return account;
+                    }
                 }
-
+            }
             return null;
         }
 
         public void Remove(string name)
         {
-            if (!m_NameCache.Contains(name))
-                return;
-
-            UUID uuid = UUID.Zero;
-            if (m_NameCache.TryGetValue(name, out uuid))
+            lock(accessLock)
             {
-                m_NameCache.Remove(name);
-                m_UUIDCache.Remove(uuid);
+                if (!m_NameCache.Contains(name))
+                    return;
+
+                UUID uuid = UUID.Zero;
+                if (m_NameCache.TryGetValue(name, out uuid))
+                {
+                    m_NameCache.Remove(name);
+                    m_UUIDCache.Remove(uuid);
+                }
             }
         }
     }