diff --git a/Bootstrap.DataAccess/DbManager.cs b/Bootstrap.DataAccess/DbManager.cs
index 0ea0ef27..d1c407f9 100644
--- a/Bootstrap.DataAccess/DbManager.cs
+++ b/Bootstrap.DataAccess/DbManager.cs
@@ -9,6 +9,7 @@ namespace Bootstrap.DataAccess
     /// </summary>
     public static class DbManager
     {
+        private static readonly object _locker = new object();
         /// <summary>
         /// 
         /// </summary>
@@ -16,7 +17,13 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static IDatabase Create(string connectionName = null, bool keepAlive = false)
         {
-            if (Mappers.GetMapper(typeof(Exceptions), null) == null) Mappers.Register(typeof(Exceptions).Assembly, new BootstrapDataAccessConventionMapper());
+            if (Mappers.GetMapper(typeof(Exceptions), null) == null)
+            {
+                lock (_locker)
+                {
+                    if (Mappers.GetMapper(typeof(Exceptions), null) == null) Mappers.Register(typeof(Exceptions).Assembly, new BootstrapDataAccessConventionMapper());
+                }
+            }
             var db = Longbow.Data.DbManager.Create(connectionName, keepAlive);
             db.ExceptionThrown += (sender, args) => args.Exception.Log(new NameValueCollection() { ["LastCmd"] = db.LastCommand });
             return db;