Entity Framework SaveChanges not saving to the database

My code isn't erroring out or anything when I put a try catch around it, but yet it still does not save to the database. Is there something I am missing?

var newGroupMemberOf = new GroupMemberOf();
newGroupMemberOf.SamAcName = accountName;
newGroupMemberOf.MemberOf = parentSameAcName;
newGroupMemberOf.DateCreated = DateTime.Now;
newGroupMemberOf.DateUpdated = DateTime.Now;
newGroupMemberOf.IsActive = true;
newGroupMemberOf.Hidden = hidden;
newGroupMemberOf.ID = 12345678;

UserEntities.GroupMemberOf.Add(newGroupMemberOf);

UserEntities.SaveChanges();

and my entity set looks sort of like

public partial class UsersEntities : DbContext 
{ 
 public UsersEntities() 
    : base("name=UsersEntities") 
{ 
} 

protected override void OnModelCreating(DbModelBuilder modelBuilder) 
 {
  throw new UnintentionalCodeFirstException(); 
 }

 public virtual DbSet<GroupMemberOf> GroupMemberOf { get; set; }