diff --git a/src/Umbraco.Core/Models/Rdbms/MemberDto.cs b/src/Umbraco.Core/Models/Rdbms/MemberDto.cs
index e5f7b3f17c..cbe9f909f8 100644
--- a/src/Umbraco.Core/Models/Rdbms/MemberDto.cs
+++ b/src/Umbraco.Core/Models/Rdbms/MemberDto.cs
@@ -22,6 +22,7 @@ namespace Umbraco.Core.Models.Rdbms
         [Column("LoginName")]
         [Length(1000)]
         [Constraint(Default = "''")]
+        [Index(IndexTypes.NonClustered, Name = "IX_cmsMember_LoginName")]
         public string LoginName { get; set; }
 
         [Column("Password")]
diff --git a/src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSevenSixZero/AddIndexToCmsMemberLoginName.cs b/src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSevenSixZero/AddIndexToCmsMemberLoginName.cs
new file mode 100644
index 0000000000..beff4b3210
--- /dev/null
+++ b/src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSevenSixZero/AddIndexToCmsMemberLoginName.cs
@@ -0,0 +1,42 @@
+using System.Linq;
+using Umbraco.Core.Logging;
+using Umbraco.Core.Persistence.DatabaseModelDefinitions;
+using Umbraco.Core.Persistence.SqlSyntax;
+
+namespace Umbraco.Core.Persistence.Migrations.Upgrades.TargetVersionSevenSixZero
+{
+    [Migration("7.6.0", 0, Constants.System.UmbracoMigrationName)]
+    public class AddIndexToCmsMemberLoginName : MigrationBase
+    {
+        public AddIndexToCmsMemberLoginName(ISqlSyntaxProvider sqlSyntax, ILogger logger)
+            : base(sqlSyntax, logger)
+        { }
+
+        public override void Up()
+        {
+            var dbIndexes = SqlSyntax.GetDefinedIndexes(Context.Database)
+                .Select(x => new DbIndexDefinition()
+                {
+                    TableName = x.Item1,
+                    IndexName = x.Item2,
+                    ColumnName = x.Item3,
+                    IsUnique = x.Item4
+                }).ToArray();
+
+            //make sure it doesn't already exist
+            if (dbIndexes.Any(x => x.IndexName.InvariantEquals("IX_cmsMember_LoginName")) == false)
+            {
+                Create.Index("IX_cmsMember_LoginName").OnTable("cmsMember")
+                    .OnColumn("LoginName")
+                    .Ascending()
+                    .WithOptions()
+                    .NonClustered();
+            }
+        }
+
+        public override void Down()
+        {
+            Delete.Index("IX_cmsMember_LoginName").OnTable("cmsMember");
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index 94267cf21f..1b15234fd1 100644
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -479,6 +479,7 @@
     <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenFourZero\AddUniqueIdPropertyTypeGroupColumn.cs" />
     <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenFourZero\RemoveParentIdPropertyTypeGroupColumn.cs" />
     <Compile Include="Persistence\Mappers\TaskTypeMapper.cs" />
+    <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenSixZero\AddIndexToCmsMemberLoginName.cs" />
     <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenSixZero\AddIndexToUmbracoNodePath.cs" />
     <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenSixZero\AddRelationTypeUniqueIdColumn.cs" />
     <Compile Include="Persistence\Migrations\Upgrades\TargetVersionSevenSixZero\AddMacroUniqueIdColumn.cs" />