I would support OSX more if I could get better support from Apple. I have two identical MBP's in my office -- and following the same steps, one joins the AD Do

I would support OSX more if I could get better support from Apple. I have two identical MBP's in my office -- and following the same steps, one joins the AD Domain, and the other one refuses to join the domain. Apple's support? Clueless, and refers me to the community support -- which doesn't have a definitive answer or any real help.