With the transition of MailMessage from System.Web.Mail to System.Net.Mail there were some mail header casing changes that caused mail sent to Hotmail and Live email addresses to appear as being successfully sent, but failed to arrive at the destination...

If you call Single to get an object from your DB and the object doesn't exist you will get an InvalidOperationException. return this .DataContext.MemberDaos.Single(m => m.MemberID == id); Instead of Single, use SingleOrDefault, which will return...

If you are using LINQ to insert data with RTM bits you won't find the Add method on the DataContext post Beta2. Use the InsertOnSubmit method instead.