public class ComputerModel
{
    public int MachineId { get; set; }
    public int GroupId { get; set; }
    public int SoftwareVersionId { get; set; }
    public string GroupName { get; set; }
    public string SoftwareVersion { get; set; }
    public string IPAddress { get; set; }
    public string HostName { get; set; }
    public string MACAddress { get; set; }
    public string Title { get; set; }
    public bool IsIGMonitor { get; set; }
    public string UpTime { get; set; }
    public DateTime DateEntered { get; set; }
    public string EnteredBy { get; set; }
    public Nullable<DateTime> DateUpdated { get; set; }
    public string UpdatedBy { get; set; }
    public ICollection<MachineRole> MachineRoles { get; set; }
    public ICollection<Role> Roles { get; set; }
}

var query = (from m in unitOfWork.Context.Machines
            join u in unitOfWork.Context.Users
            on m.EnteredBy equals u.UserId into EntByUser
            from EnteredByUser in EntByUser.DefaultIfEmpty()
            join u2 in unitOfWork.Context.Users
            on m.UpdatedBy equals u2.UserId into UpdByUser
            from UpdatedByUser in UpdByUser.DefaultIfEmpty()
            join g in unitOfWork.Context.Groups
            on m.GroupId equals g.GroupId into Grp
            from Groups in Grp.DefaultIfEmpty()
            join s in unitOfWork.Context.SoftwareVersions
            on m.SoftwareVersionId equals s.SoftwareVersionId into SW
            from SoftwareVersions in SW.DefaultIfEmpty()
            join mr in unitOfWork.Context.MachineRoles
            on m.MachineId equals mr.MachineId into MachRoles
            from MachineRoles in MachRoles.DefaultIfEmpty()
            join r in unitOfWork.Context.Roles
            on MachineRoles.RoleId equals r.RoleId into Rolz
            from Rolz2 in Rolz.DefaultIfEmpty()
            select new ComputerModel()
            {
                MachineId = m.MachineId,
                GroupId = m.GroupId,
                SoftwareVersionId = m.SoftwareVersionId,
                GroupName = Groups.GroupName,
                SoftwareVersion = SoftwareVersions.Version,
                IPAddress = m.IPAddress,
                HostName = m.HostName,
                MACAddress = m.MACAddress,
                Title = m.Title,
                IsIGMonitor = m.IsIGMonitor,
                UpTime = m.UpTime,
                DateEntered = m.DateEntered,
                DateUpdated = m.DateUpdated,
                EnteredBy = EnteredByUser.FirstName + " " + EnteredByUser.LastName,
                UpdatedBy = UpdatedByUser.FirstName + " " + UpdatedByUser.LastName,
                MachineRoles = m.MachineRoles,
                Roles = ?????
            }).ToList();