title: Unsupported Data Type when using SQL Data Sync to Azure
body: <p>I'd like to sync an on-premise SQL Server 2012 SP2 database to Azure using SQL Data Sync.
  When I try to do the sync I get "Unsupported Data Type" error on one of the tables for the ID_Index column:</p>
  
  <p><img src="https://i.stack.imgur.com/2QH4Z.png" alt=""></p>
  
  <p>The Azure Management Portal gives no further explanantion for the error.
  The table design in SQL Server Management Studio:</p>
  
  <p><img src="https://i.stack.imgur.com/E8gul.png" alt=""></p>
  
  <p>The table creation script:</p>
  
  <pre><code>CREATE TABLE [dbo].[FlightPlanData](
    [ID] [uniqueidentifier] NOT NULL CONSTRAINT [DF_FlightPlanData_ID]  DEFAULT (newid()),
    [Airline_ID] [int] NOT NULL,
    [FlightID_FK] [uniqueidentifier] NOT NULL,
    [FlightPlanID] [int] NOT NULL,
    [DateInserted] [datetime] NOT NULL CONSTRAINT [DF_FlightPlanData_DateInserted]  DEFAULT (getdate()),
    [Type] [varchar](20) NOT NULL CONSTRAINT [DF_FlightPlanData_Type]  DEFAULT (''),
    [FileName] [varchar](100) NOT NULL CONSTRAINT [DF_FlightPlanData_FileName]  DEFAULT (''),
    [ClientID_FK] [uniqueidentifier] NULL,
    [ID_Index] [int] IDENTITY(1,1) NOT NULL,
      CONSTRAINT [PK_FlightPlanData] PRIMARY KEY NONCLUSTERED ([ID] ASC))
  
  CREATE CLUSTERED INDEX [IX_FlightPlanData] ON [dbo].[FlightPlanData]([ID_Index] ASC)
  </code></pre>
  
  <p>The table has a GUID primary key, but it's not clustered, instead we use a clustered in index (ID_Index).
  I can't remove the ID_Index column, and I'd prefer not to make it the primary key. Is there any way to solve this? 
  I heard Azure requires a clustered index for each table, but it doesn't have to be the primary key. So what's the problem here?</p>